<PAGE>
SECURITIES AND EXCHANGE COMMISSION
WASHINGTON, D.C. 20549
SCHEDULE 13G
(Rule 13d-102)
INFORMATION TO BE INCLUDED IN STATEMENTS FILED PURSUANT
TO RULES 13d-1(b) (c), AND (d) AND AMENDMENTS THERETO FILED
PURSUANT TO RULE 13d-2(b)
(Amendment No. 1)*
-
3Dfx Interactive, Inc.
- --------------------------------------------------------------------------------
(Name of Issuer)
Common Stock
- --------------------------------------------------------------------------------
(Title of Class of Securities)
88553X103
-------------------
(CUSIP Number)
January 1, 1998
- --------------------------------------------------------------------------------
(Date of Event Which Requires Filing of this Statement)
Check the appropriate box to designate the rule pursuant to which this
Schedule is filed:
[_] Rule 13d-1(b)
[_] Rule 13d-(c)
[X] Rule 13d-1(d)
*The remainder of this cover page shall be filled out for a reporting
person's initial filing on this form with respect to the subject class of
securities, and for any subsequent amendment containing information which would
alter the disclosures provided in a prior cover page.
The information required in the remainder of this cover page shall not
be deemed to be "filed" for the purpose of Section 18 of the Securities Exchange
Act of 1934 ("Act") or otherwise subject to the liabilities of that section of
the Act but shall be subject to all other provisions of the Act (however, see
the Notes).
<PAGE>
- ----------------------- ---------------------
CUSIP NO. 88553X103 13G PAGE 2 OF 17 PAGES
- ----------------------- ---------------------
- ------------------------------------------------------------------------------
NAME OF REPORTING PERSON
1 S.S. or I.R.S. IDENTIFICATION NO. OF ABOVE PERSON
Venrock Associates
I.R.S. #13-6300995
- ------------------------------------------------------------------------------
CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP*
2 (a) [X]
(b) [_]
- ------------------------------------------------------------------------------
SEC USE ONLY
3
- ------------------------------------------------------------------------------
CITIZENSHIP OR PLACE OF ORGANIZATION
4
New York, U.S.A.
- ------------------------------------------------------------------------------
SOLE VOTING POWER
5
NUMBER OF
0
SHARES -----------------------------------------------------------
SHARED VOTING POWER
BENEFICIALLY 6
OWNED BY 607,194
-----------------------------------------------------------
EACH SOLE DISPOSITIVE POWER
7
REPORTING
0
PERSON -----------------------------------------------------------
SHARED DISPOSITIVE POWER
WITH 8
607,194
- ------------------------------------------------------------------------------
AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
9
607,194
- ------------------------------------------------------------------------------
CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES*
10
[_]
- ------------------------------------------------------------------------------
PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9)
11
4.83%
- ------------------------------------------------------------------------------
TYPE OF REPORTING PERSON*
12
PN
- ------------------------------------------------------------------------------
*SEE INSTRUCTIONS BEFORE FILLING OUT!
Page 2 of 17 pages
<PAGE>
- ----------------------- ---------------------
CUSIP NO. 88553X103 13G PAGE 3 OF 17 PAGES
- ----------------------- ---------------------
- ------------------------------------------------------------------------------
NAME OF REPORTING PERSON
1 S.S. or I.R.S. IDENTIFICATION NO. OF ABOVE PERSON
Venrock Associates II, L.P.
I.R.S. #13-3844754
- ------------------------------------------------------------------------------
CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP*
2 (a) [X]
(b) [_]
- ------------------------------------------------------------------------------
SEC USE ONLY
3
- ------------------------------------------------------------------------------
CITIZENSHIP OR PLACE OF ORGANIZATION
4
New York, U.S.A.
- ------------------------------------------------------------------------------
SOLE VOTING POWER
5
NUMBER OF
0
SHARES -----------------------------------------------------------
SHARED VOTING POWER
BENEFICIALLY 6
OWNED BY 301,044
-----------------------------------------------------------
EACH SOLE DISPOSITIVE POWER
7
REPORTING
0
PERSON -----------------------------------------------------------
SHARED DISPOSITIVE POWER
WITH 8
301,044
- ------------------------------------------------------------------------------
AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
9
301,044
- ------------------------------------------------------------------------------
CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES*
10
[_]
- ------------------------------------------------------------------------------
PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9)
11
2.39%
- ------------------------------------------------------------------------------
TYPE OF REPORTING PERSON*
12
PN
- ------------------------------------------------------------------------------
*SEE INSTRUCTIONS BEFORE FILLING OUT!
Page 3 of 17 pages
<PAGE>
- ----------------------- ---------------------
CUSIP NO. 88553X103 13G PAGE 4 OF 17 PAGES
- ----------------------- ---------------------
- ------------------------------------------------------------------------------
NAME OF REPORTING PERSON
1 S.S. or I.R.S. IDENTIFICATION NO. OF ABOVE PERSON
Anthony B. Evnin
###-##-####
- ------------------------------------------------------------------------------
CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP*
2 (a) [X]
(b) [_]
- ------------------------------------------------------------------------------
SEC USE ONLY
3
- ------------------------------------------------------------------------------
CITIZENSHIP OR PLACE OF ORGANIZATION
4
U.S.A.
- ------------------------------------------------------------------------------
SOLE VOTING POWER
5
NUMBER OF
17,569
SHARES -----------------------------------------------------------
SHARED VOTING POWER
BENEFICIALLY 6
OWNED BY 908,238
-----------------------------------------------------------
EACH SOLE DISPOSITIVE POWER
7
REPORTING
17,569
PERSON -----------------------------------------------------------
SHARED DISPOSITIVE POWER
WITH 8
908,238
- ------------------------------------------------------------------------------
AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
9
925,807
- ------------------------------------------------------------------------------
CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES*
10
[_]
- ------------------------------------------------------------------------------
PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9)
11
7.36%
- ------------------------------------------------------------------------------
TYPE OF REPORTING PERSON*
12
IN
- ------------------------------------------------------------------------------
*SEE INSTRUCTIONS BEFORE FILLING OUT!
Page 4 of 17 pages
<PAGE>
- ----------------------- ---------------------
CUSIP NO. 88553X103 13G PAGE 5 OF 17 PAGES
- ----------------------- ---------------------
- ------------------------------------------------------------------------------
NAME OF REPORTING PERSON
1 S.S. or I.R.S. IDENTIFICATION NO. OF ABOVE PERSON
David R. Hathaway
###-##-####
- ------------------------------------------------------------------------------
CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP*
2 (a) [X]
(b) [_]
- ------------------------------------------------------------------------------
SEC USE ONLY
3
- ------------------------------------------------------------------------------
CITIZENSHIP OR PLACE OF ORGANIZATION
4
U.S.A.
- ------------------------------------------------------------------------------
SOLE VOTING POWER
5
NUMBER OF
21,919
SHARES -----------------------------------------------------------
SHARED VOTING POWER
BENEFICIALLY 6
OWNED BY 908,238
-----------------------------------------------------------
EACH SOLE DISPOSITIVE POWER
7
REPORTING
21,919
PERSON -----------------------------------------------------------
SHARED DISPOSITIVE POWER
WITH 8
908,238
- ------------------------------------------------------------------------------
AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
9
930,157
- ------------------------------------------------------------------------------
CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES*
10
[_]
- ------------------------------------------------------------------------------
PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9)
11
7.39%
- ------------------------------------------------------------------------------
TYPE OF REPORTING PERSON*
12
IN
- ------------------------------------------------------------------------------
*SEE INSTRUCTIONS BEFORE FILLING OUT!
Page 5 of 17 pages
<PAGE>
- ----------------------- ---------------------
CUSIP NO. 88553X103 13G PAGE 6 OF 17 PAGES
- ----------------------- ---------------------
- ------------------------------------------------------------------------------
NAME OF REPORTING PERSON
1 S.S. or I.R.S. IDENTIFICATION NO. OF ABOVE PERSON
Patrick F. Latterell
###-##-####
- ------------------------------------------------------------------------------
CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP*
2 (a) [X]
(b) [_]
- ------------------------------------------------------------------------------
SEC USE ONLY
3
- ------------------------------------------------------------------------------
CITIZENSHIP OR PLACE OF ORGANIZATION
4
U.S.A.
- ------------------------------------------------------------------------------
SOLE VOTING POWER
5
NUMBER OF
16,964
SHARES -----------------------------------------------------------
SHARED VOTING POWER
BENEFICIALLY 6
OWNED BY 908,238
-----------------------------------------------------------
EACH SOLE DISPOSITIVE POWER
7
REPORTING
16,964
PERSON -----------------------------------------------------------
SHARED DISPOSITIVE POWER
WITH 8
908,238
- ------------------------------------------------------------------------------
AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
9
925,202
- ------------------------------------------------------------------------------
CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES*
10
[_]
- ------------------------------------------------------------------------------
PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9)
11
7.36%
- ------------------------------------------------------------------------------
TYPE OF REPORTING PERSON*
12
IN
- ------------------------------------------------------------------------------
*SEE INSTRUCTIONS BEFORE FILLING OUT!
Page 6 of 17 pages
<PAGE>
- ----------------------- ---------------------
CUSIP NO. 88553X103 13G PAGE 7 OF 17 PAGES
- ----------------------- ---------------------
- ------------------------------------------------------------------------------
NAME OF REPORTING PERSON
1 S.S. or I.R.S. IDENTIFICATION NO. OF ABOVE PERSON
Ted H. McCourtney
###-##-####
- ------------------------------------------------------------------------------
CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP*
2 (a) [X]
(b) [_]
- ------------------------------------------------------------------------------
SEC USE ONLY
3
- ------------------------------------------------------------------------------
CITIZENSHIP OR PLACE OF ORGANIZATION
4
U.S.A.
- ------------------------------------------------------------------------------
SOLE VOTING POWER
5
NUMBER OF
23,886
SHARES -----------------------------------------------------------
SHARED VOTING POWER
BENEFICIALLY 6
OWNED BY 908,238
-----------------------------------------------------------
EACH SOLE DISPOSITIVE POWER
7
REPORTING
23,886
PERSON -----------------------------------------------------------
SHARED DISPOSITIVE POWER
WITH 8
908,238
- ------------------------------------------------------------------------------
AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
9
932,124
- ------------------------------------------------------------------------------
CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES*
10
[_]
- ------------------------------------------------------------------------------
PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9)
11
7.41%
- ------------------------------------------------------------------------------
TYPE OF REPORTING PERSON*
12
IN
- ------------------------------------------------------------------------------
*SEE INSTRUCTIONS BEFORE FILLING OUT!
Page 7 of 17 pages
<PAGE>
- ----------------------- ---------------------
CUSIP NO. 88553X103 13G PAGE 8 OF 17 PAGES
- ----------------------- ---------------------
- ------------------------------------------------------------------------------
NAME OF REPORTING PERSON
1 S.S. or I.R.S. IDENTIFICATION NO. OF ABOVE PERSON
Ray A. Rothrock
###-##-####
- ------------------------------------------------------------------------------
CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP*
2 (a) [X]
(b) [_]
- ------------------------------------------------------------------------------
SEC USE ONLY
3
- ------------------------------------------------------------------------------
CITIZENSHIP OR PLACE OF ORGANIZATION
4
U.S.A.
- ------------------------------------------------------------------------------
SOLE VOTING POWER
5
NUMBER OF
16,058
SHARES -----------------------------------------------------------
SHARED VOTING POWER
BENEFICIALLY 6
OWNED BY 908,238
-----------------------------------------------------------
EACH SOLE DISPOSITIVE POWER
7
REPORTING
16,058
PERSON -----------------------------------------------------------
SHARED DISPOSITIVE POWER
WITH 8
908,238
- ------------------------------------------------------------------------------
AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
9
924,296
- ------------------------------------------------------------------------------
CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES*
10
[_]
- ------------------------------------------------------------------------------
PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9)
11
7.35%
- ------------------------------------------------------------------------------
TYPE OF REPORTING PERSON*
12
IN
- ------------------------------------------------------------------------------
*SEE INSTRUCTIONS BEFORE FILLING OUT!
Page 8 of 17 pages
<PAGE>
- ----------------------- ---------------------
CUSIP NO. 88553X103 13G PAGE 9 OF 17 PAGES
- ----------------------- ---------------------
- ------------------------------------------------------------------------------
NAME OF REPORTING PERSON
1 S.S. or I.R.S. IDENTIFICATION NO. OF ABOVE PERSON
Kimberley A. Rummelsburg
###-##-####
- ------------------------------------------------------------------------------
CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP*
2 (a) [X]
(b) [_]
- ------------------------------------------------------------------------------
SEC USE ONLY
3
- ------------------------------------------------------------------------------
CITIZENSHIP OR PLACE OF ORGANIZATION
4
U.S.A.
- ------------------------------------------------------------------------------
SOLE VOTING POWER
5
NUMBER OF
0
SHARES -----------------------------------------------------------
SHARED VOTING POWER
BENEFICIALLY 6
OWNED BY 910,810
-----------------------------------------------------------
EACH SOLE DISPOSITIVE POWER
7
REPORTING
0
PERSON -----------------------------------------------------------
SHARED DISPOSITIVE POWER
WITH 8
910,810
- ------------------------------------------------------------------------------
AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
9
910,810
- ------------------------------------------------------------------------------
CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES*
10
[_]
- ------------------------------------------------------------------------------
PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9)
11
7.25%
- ------------------------------------------------------------------------------
TYPE OF REPORTING PERSON*
12
IN
- ------------------------------------------------------------------------------
*SEE INSTRUCTIONS BEFORE FILLING OUT!
Page 9 of 17 pages
<PAGE>
- ----------------------- ---------------------
CUSIP NO. 88553X103 13G PAGE 10 OF 17 PAGES
- ----------------------- ---------------------
- ------------------------------------------------------------------------------
NAME OF REPORTING PERSON
1 S.S. or I.R.S. IDENTIFICATION NO. OF ABOVE PERSON
Anthony Sun
###-##-####
- ------------------------------------------------------------------------------
CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP*
2 (a) [X]
(b) [_]
- ------------------------------------------------------------------------------
SEC USE ONLY
3
- ------------------------------------------------------------------------------
CITIZENSHIP OR PLACE OF ORGANIZATION
4
U.S.A.
- ------------------------------------------------------------------------------
SOLE VOTING POWER
5
NUMBER OF
32,150
SHARES -----------------------------------------------------------
SHARED VOTING POWER
BENEFICIALLY 6
OWNED BY 908,238
-----------------------------------------------------------
EACH SOLE DISPOSITIVE POWER
7
REPORTING
32,150
PERSON -----------------------------------------------------------
SHARED DISPOSITIVE POWER
WITH 8
908,238
- ------------------------------------------------------------------------------
AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
9
940,388
- ------------------------------------------------------------------------------
CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES*
10
[_]
- ------------------------------------------------------------------------------
PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9)
11
7.48%
- ------------------------------------------------------------------------------
TYPE OF REPORTING PERSON*
12
IN
- ------------------------------------------------------------------------------
*SEE INSTRUCTIONS BEFORE FILLING OUT!
Page 10 of 17 pages
<PAGE>
Introduction: This Amendment No. 1 amends a Statement on Schedule 13G (the
"Schedule") filed with the Securities and Exchange Commission on February 14,
1997 on behalf of Venrock Associates, a limited partnership organized under the
laws of the State of New York, Venrock Associates II, L.P., a limited
partnership organized under the laws of the State of New York, Anthony B. Evnin,
David R. Hathaway, Patrick F. Latterell, Ted H. McCourtney, Ray A. Rothrock,
Kimberley A. Rummelsburg and Anthony Sun in respect of shares of Common Stock of
3Dfx Interactive, Inc.
Item 1(a) Name of Issuer
- --------------------------------
3Dfx Interactive, Inc.
Item 1(b) Address of Issuer's Principal Executive Offices
- -----------------------------------------------------------------
4435 Fortran Drive
San Jose, CA 95134
Item 2(a) Name of Person Filing
- ---------------------------------------
Venrock Associates ("Venrock")
Venrock Associates II, L.P. ("Venrock II")
Anthony B. Evnin
David R. Hathaway
Patrick F. Latterell
Ted H. McCourtney
Ray A. Rothrock
Kimberley A. Rummelsburg
Anthony Sun
Item 2(b) Address of Principal Business Office or, if none, Residence
- -----------------------------------------------------------------------------
New York Office: Menlo Park Office:
30 Rockefeller Plaza 2494 Sand Hill Road
Room 5508 Suite 200
New York, NY 10112 Menlo Park, CA 94025
Item 2(c) Citizenship
- -----------------------------
Venrock and Venrock II are limited partnerships organized in
the State of New York. Anthony B. Evnin, David R. Hathaway,
Patrick F. Latterell, Ted H. McCourtney, Ray A. Rothrock,
Kimberley A. Rummelsburg and Anthony Sun are General
Partners of Venrock and Venrock II and all are citizens of
the United States of America.
Item 2(d) Title of Class of Securities
- ----------------------------------------------
Common Stock
Item 2(e) CUSIP Number
- ------------------------------
88553X103
Item 3 Not applicable.
- ------
Page 11 of 17 pages
<PAGE>
Item 4 Ownership
- -------------------------
(a) and (b)
Venrock owns 607,194 shares or 4.83% of the outstanding shares
of common stock. Venrock II owns 301,044 shares or 2.39% of the
outstanding shares of common stock.
Anthony B. Evnin beneficially owns 925,807 shares or 7.36% of
the outstanding shares of common stock. David R. Hathaway
beneficially owns 930,157 shares or 7.39% of the outstanding
shares of common stock. Patrick F. Latterell beneficially owns
925,202 shares or 7.36% of the outstanding shares of common
stock. Ted H. McCourtney beneficially owns 932,124 shares or
7.41% of the outstanding shares of common stock. Ray A. Rothrock
beneficially owns 924,296 shares or 7.35% of the outstanding
shares of common stock. Kimberley A. Rummelsburg beneficially
owns 910,810 shares or 7.25% of the outstanding shares of common
stock. Anthony Sun beneficially owns 940,388 shares or 7.48% of
the outstanding shares of common stock.
(c)
Anthony B. Evnin has sole voting and dispositive power over
17,569 shares of common stock and shared voting and dispositive
power over 908,238 shares of common stock. David R. Hathaway has
sole voting and dispositive power over 21,919 shares of common
stock and shared voting and dispositive power over 908,238
shares of common stock. Patrick F. Latterell has sole voting and
dispositive power over 16,964 shares of common stock and shared
voting and dispositive power over 908,238 shares of common
stock. Ted H. McCourtney has sole voting and dispositive power
over 23,886 shares of common stock and shared voting and
dispositive power over 908,238 shares of common stock. Ray A.
Rothrock has sole voting and dispositive power over 16,058
shares of common stock and shared voting and dispositive power
over 908,238 shares of common stock. Kimberley A. Rummelsburg
has sole voting and dispositive power over no shares of common
stock and shared voting and dispositive power over 910,810
shares of common stock. Anthony Sun has sole voting and
dispositive power over 32,150 shares of common stock and shared
voting and dispositive powers over 908,238 shares of common
stock.
Item 5 Ownership of Five Percent or Less of a Class
- ------------------------------------------------------------
If this statement is being filed to report the fact that as of
the date hereof the reporting person has ceased to be the
beneficial owner of more than five percent of the class of
securities, check the following [ ].
Item 6 Ownership of More than Five Percent of Behalf of Another Person
- ---------------------------------------------------------------------
No person, other than the General Partners of Venrock and
Venrock II, has the right to receive or the power to direct the
receipt of dividends from, or the proceeds from the sale of, the
shares of common stock owned by Venrock and Venrock II.
Item 7 Identification and Classification of the Subsidiary which
- -------------------------------------------------------------------------
Acquired the Security Being Reported on by the Parent Holding
-------------------------------------------------------------
Company
-------
Not applicable.
Item 8 Identification and Classification of Members of the Group
- -------------------------------------------------------------------------
This schedule is being filed pursuant to Rule 13d-1(d). The
identities of the seven General Partners of Venrock and Venrock
II are stated in Item 2.
Item 9 Notice of Dissolution of Group
- ----------------------------------------------
Not applicable.
Page 12 of 17 pages
<PAGE>
Item 10 Certification
- -----------------------------
Not applicable.
Page 13 of 17 pages
<PAGE>
SIGNATURE
After reasonable inquiry and to the best of my knowledge and belief, I
certify that the information set forth in this Statement is true, complete and
correct.
February 9, 1999 VENROCK ASSOCIATES
By: /s/ Ted H. McCourtney
---------------------
Ted H. McCourtney
General Partner
February 9, 1999 VENROCK ASSOCIATES II, L.P.
By: /s/ Ted H. McCourtney
---------------------
Ted H. McCourtney
General Partner
February 9, 1999 GENERAL PARTNERS
*
------------------------------
Anthony B. Evnin
*
------------------------------
David R. Hathaway
*
------------------------------
Patrick F. Latterell
*
------------------------------
Ted H. McCourtney
*
------------------------------
Ray A. Rothrock
*
------------------------------
Kimberley A. Rummelsburg
*
------------------------------
Anthony Sun
* By: /s/ Ted H. McCourtney
---------------------
Ted H. McCourtney
Attorney-in-Fact
Page 14 of 17 pages
<PAGE>
Exhibit Index
Page No.
24.1 Power of Attorney dated as of February 13, 1998 16
granted by the General Parnters in favor of
Mr. Ted H. McCourtney
99.1 Agreement pursuant to 13d-1(k)(1) among Venrock 17
Associates, Venrock Associates II, L.P. and the
General Partners thereof
Page 15 of 17 pages
<PAGE>
Exhibit 24.1
POWER OF ATTORNEY
KNOWN ALL MEN BY THESE PRESENTS that each person whose signature appears below
constitutes and appoints Ted H. McCourtney his or her true and lawful attorney-
in-fact and agent, acting alone, with full power of substitution and
resubstitution, for him or her and in his or her name, place and stead, in any
and all capacities, to sign the Schedule 13G, and all amendments thereto, with
all exhibits thereto, and all documents in connection therewith, with respect to
the beneficial ownership by the undersigned of the equity securities of 3Dfx
Interactive, Inc., and to file the same, with the Securities and Exchange
Commission and any other person, granting unto the attorney-in-fact and agent
full power and authority to do and perform each and every act and thing
requisite and necessary to be done in and about the premises, as fully to all
intents and purposes as he or she might or could do in person, and hereby
ratifies and confirms all that said attorney-in-fact and agent or his substitute
or substitutes, may lawfully do or cause to be done.
February 13, 1998 /s/ Mark W. Bailey
--------------------------------
Mark W. Bailey
General Partner
/s/ Anthony B. Evnin
--------------------------------
Anthony B. Evnin
General Partner
/s/ David R. Hathaway
--------------------------------
David R. Hathaway
General Partner
/s/ Ted H. McCourtney
--------------------------------
Ted H. McCourtney
General Partner
/s/ Ray A. Rothrock
--------------------------------
Ray A. Rothrock
General Partner
/s/ Kimberley A. Rummelsburg
---------------------------------
Kimberley A. Rummelsburg
General Partner
/s/ Patrick F. Latterell
---------------------------------
Patrick F. Latterell
General Partner
/s/ Anthony Sun
---------------------------------
Anthony Sun
General Partner
Page 16 of 17 pages
<PAGE>
Exhibit 99.1
------------
AGREEMENT
Pursuant to Rule 13d-1(k)(1) promulgated pursuant to the Securities
Exchange Act of 1934, as amended, the undersigned agree that the attached
Schedule 13G is being filed on behalf of each of the undersigned.
February 9, 1999 VENROCK ASSOCIATES
By: /s/ Ted H. McCourtney
---------------------
Ted H. McCourtney
General Partner
February 9, 1999 VENROCK ASSOCIATES II, L.P.
By: /s/ Ted H. McCourtney
---------------------
Ted H. McCourtney
General Partner
February 9, 1999 GENERAL PARTNERS
*
------------------------------
Anthony B. Evnin
*
------------------------------
David R. Hathaway
*
------------------------------
Patrick F. Latterell
*
------------------------------
Ted H. McCourtney
*
------------------------------
Ray A. Rothrock
*
------------------------------
Kimberley A. Rummelsburg
*
------------------------------
Anthony Sun
* By: /s/ Ted H. McCourtney
---------------------
Ted H. McCourtney
Attorney-in-Fact
Page 17 of 17 pages
