
                                                              Exhibit 5.1
Wilson Sonsini Goodrich & Rosati
Professional Corporation
650 Page Mill Road
Palo Alto, CA 94304


May 19, 1999


3Dfx Interactive, Inc.
4435 Fortran Drive
San Jose, California 95134

Re:     Registration Statement on Form S-8

Gentlemen:
We have examined the Registration Statement on Form S-8 to be 
filed by you with the Securities and Exchange Commission on or about 
May 19, 1999 (the "Registration Statement") in connection with the 
registration under the Securities Act of 1933, as amended, of an 
aggregate of 813,000 shares of your Common Stock, no par value, (the 
"Shares") to be issued pursuant to individual options granted under the 
STB Systems, Inc. 1995 Amended and Restated Long Term Incentive Plan, 
the STB Systems, Inc. Amended and Restated Stock Option Plan for Non-
Employee Directors and pursuant to the STB Systems, Inc. 1995 Employee 
Stock Option Purchase Plan (collectively, the "Plans").  As your 
counsel in connection with this transaction, we have examined the 
proceedings taken and are familiar with the proceedings proposed to be 
taken by you in connection with the issuance and sale of the Shares 
pursuant to the Plans.

It is our opinion that, when issued and sold in the manner 
described in the Plans and pursuant to the agreements which accompany 
each grant under the Plans, the Shares will be legally and validly 
issued, fully-paid and non-assessable.
We consent to the use of this opinion as an exhibit to the 
Registration Statement, and further consent to the use of our name 
wherever appearing in the Registration Statement and any amendments 
thereto.
Very truly yours,

WILSON SONSINI GOODRICH & ROSATI
Professional Corporation
/S/ WILSON SONSINI GOODRICH & ROSATI

