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                                                                 Exhibit 10.3

              AMENDMENT TO EMPLOYMENT AGREEMENT FOR EXECUTIVE OFFICER

     THIS AMENDMENT TO EMPLOYMENT AGREEMENT FOR EXECUTIVE OFFICER 
("Agreement") made the 13TH  day of December, 1998, between STB SYSTEMS, 
INC., a Texas corporation (the "Company"), and JAMES L. HOPKINS  
("Executive").

     WHEREAS, Executive and the Company have executed an Employment Agreement 
dated as of November 1, 1996 (the "Employment Agreement"); and

     WHEREAS, under an Agreement and Plan of Reorganization dated as of 
December 13, 1998 (the "Merger Agreement"), the Company will become a 
wholly-owned subsidiary of 3Dfx Interactive, Inc., a California corporation 
("3Dfx"); as of the Effective Time (as defined in the Merger Agreement) (the 
"Merger"); and

     WHEREAS, at the Effective Time of the Merger, 3Dfx will assume the 
Employment Agreement and become the employer thereunder; and 

     WHEREAS, Executive and the Company desire to set forth in this Agreement 
the amended terms for Executive's continued employment following the Merger. 

     NOW, THEREFORE, in consideration of the mutual covenants and agreements 
herein contained, the parties agree as follows:

                                  FIRST

     The terms of this Agreement shall become effective only at the Effective 
Time of the Merger, at which time 3Dfx shall assume the Employment Agreement, 
as amended by this Agreement, and all references in such Employment Agreement 
and this Agreement to the "Company" shall be deemed to refer to 3Dfx.  
Paragraphs 1 and 2 of the Employment Agreement will be amended in their 
entirety to provide as follows:

"1.  EMPLOYMENT.  The Company hereby agrees to employ Executive and Executive 
hereby agrees to serve the Company, on the terms and conditions set forth 
herein, for the period commencing on the Effective Time of the Merger and 
expiring on the date that is the one year anniversary of such date (unless 
sooner terminated as hereinafter set forth); provided, however, that 
commencing on such anniversary date, and each annual anniversary of such date 
thereafter, the term of this Agreement shall automatically be extended for 
one additional year unless, at least 30 days prior to any such anniversary 
date, the Company or the Executive shall have given notice that it does not 
wish to extend this Agreement.  The term of this Agreement, as it may from 
time to time be extended in accordance with this Paragraph, may be referred 
to herein as the "Period of Employment."

     2.   POSITION AND DUTIES.  Executive shall serve as the Senior Vice 
President for Finance & Strategic Planning for the Company, performing the 
functions and duties as shall be prescribed from time to time provided that 
such functions and duties are consistent with and attendant to Executive's 
position or other positions that he may hold from time to time.  Executive 
shall devote his full working time and efforts to the business and affairs of 
the

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Company and the promotion of its interests and perform all duties and 
services on behalf of the Company necessary to carry out such functions."

                                  SECOND

     Subparagraph 3c of the Employment Agreement will be deleted in its 
entirety.  Subparagraphs 3a and 3b of the Employment Agreement will be 
amended in their entirety to read as follows:

     "3.  COMPENSATION AND RELATED MATTERS.

          a.   BASE SALARY. Executive shall receive an annual base salary 
("Base Salary") at the rate of Two Hundred Twenty-five Thousand Dollars and 
No/100 Cents ($225,000.00) during the period ending on the first anniversary 
of the Effective Time of the Merger.  Thereafter, Executive's Base Salary 
shall be redetermined at least 30 days before each annual anniversary in an 
amount to be fixed by the Board of Directors of the Company or the 
Compensation Committee thereof.  The term "Base Salary" as used in this 
Agreement shall mean, at any point in time, Executive's annual base salary at 
such time.  The Base Salary shall be payable in substantially equal 
semi-monthly installments or in accordance with the Company's regular payroll 
practices.

          b.   INCENTIVE COMPENSATION.  In addition to Base Salary, Executive 
shall participate in the Company's incentive compensation plan for its senior 
executive management employees." 

                                     THIRD

     Subparagraph 9c of the Employment Agreement will be amended to delete 
therefrom Subsection (A) in its entirety.  Subsection (C) of the definition 
of "Good Reason" in Subparagraph 9d of the Employment Agreement will be 
amended in its entirety to reflect more clearly the original intent of the 
parties, to read as follows:

     "(C) without Executive's consent, a reduction of Executive's Base Salary 
to an amount less than previously determined and fixed for the immediately 
preceding twelve-month period by the Compensation Committee in accordance 
with Subparagraph 3(a) other than a reduction deemed necessary by the Board 
for all executive officers;"

                                    FOURTH

     Paragraph 11 of the Employment Agreement will be amended by substituting 
the following paragraph in lieu of the first paragraph thereof:

     "The provisions of this Paragraph 11 of the Agreement set forth certain 
terms of an agreement reached between Executive and the Company regarding 
Executive's rights and obligations upon the occurrence of a Change in Control 
of the Company.  These provisions are intended to assure and encourage in 
advance Executive's continued attention and dedication to his assigned duties 
and his objectivity during the pendency and after the occurrence of any such 
event. These

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provisions shall apply in lieu of, and expressly supersede, the provisions of 
Subparagraph 10(d)(ii) regarding severance pay upon a termination of 
employment, if such termination of employment occurs within 12 months after 
the occurrence of the first event constituting a Change of Control, or if 
such termination of employment occurs under certain circumstances after the 
Merger. These provisions shall terminate and be of no further force or effect 
12 months after the occurrence of a Change of Control or, the Merger, as the 
case may be, Section 11(c) shall be the sole provision under which payments 
may be made in connection with the Merger; that is, to the extent Section 
11(c) applies, Section 11(b) shall not."

                                      FIFTH


     Paragraph 11 of the Employment Agreement will be amended by adding the 
following subparagraph (c), and by renumbering the current subparagraph (c) 
as subparagraph (d):

     "(c) TERMINATION OF EMPLOYMENT FOLLOWING THE MERGER.  If Executive's 
employment terminates during the 12 months following consummation of the 
Merger for any reason (other than his Voluntary Resignation on or prior to 
May 31, 1999), the Company shall pay Executive or his estate an amount equal 
to the applicable Parachute Payment Amount in a lump sum on the thirtieth day 
following Executive's termination. After the first anniversary of the Merger, 
this Section 11(c) shall be of no-force and effect. For purposes of this 
subparagraph 11(c) only, the Severance Payment Amount payable under 
Subparagraph 10(d)(ii) hereof shall be computed utilizing Executive's Base 
Salary in effect on October 31, 1998, Executive's incentive compensation 
earned in the eight full quarters ending October 31, 1998, and Executive's 
sales commissions earned in the 24 full months preceding October 31, 1998."

                                      SIXTH

     Paragraph 11(d) of the Employment Agreement will be amended by adding 
the following provision:

     "MERGER" shall mean the Change in Control occurring as a result of the 
merger of a newly formed, wholly-owned subsidiary of 3Dfx with and into STB 
Systems, Inc., in accordance with that certain Merger Agreement dated as of 
December 13, 1998."

                                      SEVENTH

     Paragraph 12 of the Employment Agreement will be amended in its entirety 
to provide as follows:

     "12. NOTICE.  For purposes of this Agreement, notices and all other 
communications provided for in the Agreement shall be in writing and shall be 
deemed to have been duly given when delivered or mailed by United States 
certified mail, return receipt requested, postage prepaid, addressed as 
follows:

     if to the Executive:

          At his home address as shown
          in the Company's personnel records;

     if to the Company:

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

or to such other address as either party may have furnished to the other in 
writing in accordance herewith, except that notices of change of address 
shall be effective only upon receipt."

     IN WITNESS WHEREOF, the parties have executed this Agreement on the date 
set forth above.

                                        STB SYSTEMS, INC.

/s/ James L. Hopkins                         /s/ William E. Ogle
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JAMES L. HOPKINS                        By:
                                        Its.:  Chief Executive Officer
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