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                                                                     Exhibit 5.1

                        WILSON SONSINI GOODRICH & ROSATI
                            PROFESSIONAL CORPORATION
                                  [LETTERHEAD]

                  
                                  May 22, 1997



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

        RE:  REGISTRATION STATEMENT ON FORM S-1
             FILE NO. 333-25365
             ----------------------------------

Ladies and Gentlemen:

        We have examined the Registration Statement on Form S-1 filed by you
with the Securities and Exchange Commission on April 17, 1997 (Registration No.
333-25365) (the "Registration Statement"), in connection with the registration
under the Securities Act of 1933, as amended, of the shares of Common Stock
registered pursuant to the Registration Statement (the "Shares"). The Shares are
to be sold as described in the Registration Statement. As your counsel in
connection with this transaction, we have examined the proceedings taken and
proposed to be taken in connection with said sale and issuance of the Shares.

        It is our opinion that the Shares, when issued and sold in the manner
referred to in the Registration Statement, will be legally and validly issued,
fully paid and nonassessable.

        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, including the Prospectuses constituting a part thereof,
and any amendment thereto.

                                Very truly yours,

                                WILSON SONSINI GOODRICH & ROSATI
                                Professional Corporation

                                /s/ WILSON SONSINI GOODRICH & ROSATI


