<PAGE>

                                                                    Exhibit 10.3
 

THIS WARRANT HAS NOT BEEN REGISTERED UNDER THE SECURITIES ACT OF 1933, AS
AMENDED, OR ANY APPLICABLE STATE SECURITIES LAWS, AND MAY NOT BE SOLD OR
TRANSFERRED UNLESS SUCH SALE OR TRANSFER IS IN ACCORDANCE WITH THE REGISTRATION
REQUIREMENTS OF SUCH ACT AND APPLICABLE LAWS OR SOME OTHER EXEMPTION FROM THE
REGISTRATION REQUIREMENTS OF SUCH ACT AND APPLICABLE LAWS IS AVAILABLE WITH
RESPECT THERETO.


             SERIES A CONVERTIBLE PREFERRED STOCK PURCHASE WARRANT

Warrant No. 1

                   NUMBER NINE VISUAL TECHNOLOGY CORPORATION
                   -----------------------------------------
                                        

                  Void after Expiration Date (defined herein)


   1.  Issuance.  This Warrant is issued to Silicon Graphics, Inc. ("SGI"), a
       --------                                                      ---     
Delaware corporation, by Number Nine Visual Technology Corporation, a Delaware
corporation (hereinafter with its successors called the "Company").
                                                         -------   

   2.  Purchase Price; Number of Shares.
       -------------------------------- 

       (a) Subject to the terms and conditions hereinafter set forth, the
registered holder of this Warrant (the "Holder"), commencing on the Exercise
                                        ------                              
Date (as defined herein), is entitled upon surrender of this Warrant with the
subscription form annexed hereto duly executed, at the office of the Company, 18
Hartwell Avenue, Lexington, Massachusetts  02173, or such other office as the
Company shall notify the Holder of in writing, to purchase from the Company at a
price per share (the "Purchase Price") of $2.75, the Warrant Shares (as defined
                      --------------                                           
herein).  Until such time as this Warrant is exercised in full or expires, the
Purchase Price and the Warrant Shares issuable upon exercise of this Warrant are
subject to adjustment as hereinafter provided.

       (b) For purposes hereof, "Warrant Shares" shall be that number of fully
paid and nonassessable shares of Series A Convertible Preferred Stock, $.01 par
value, of the Company (the "Series A Preferred Stock") as are convertible into
                            ------------------------                          
shares of the Company's Common Stock, $.01 par value per share (the "Common
                                                                     ------
Stock") equal to three percent (3%) of the Company's issued and outstanding
-----                                                                      
Common Stock, calculated on a fully diluted basis (excluding the Series A
Preferred Stock and any warrants or options that are not "in-the-money") as of
the Exercise Date.

<PAGE>
 
                                      -2-


       (c) For purposes hereof, "Exercise Date" shall mean the date upon which
the Company pays any outstanding principal and interest due under any of the
secured subordinated convertible promissory notes (the "Notes") issued pursuant
                                                        -----                  
to a Securities Purchase Agreement dated May 7, 1998 by and between the Company
and the Investor; provided, however, that if the Holder converts any portion of
                  --------  -------                                            
the Notes into equity, the Warrant shall not be exercisable.

   3.  Payment of Purchase Price.  The Purchase Price may be paid (i) in cash or
       -------------------------                                                
by check, (ii) by the surrender by the Holder to the Company of any promissory
notes or other obligations issued by the Company, with all such notes and
obligations so surrendered being credited against the Purchase Price in an
amount equal to the principal amount thereof plus accrued interest to the date
of surrender, (iii) by any combination of the foregoing.

   4.  Partial Exercise.  This Warrant may be exercised in part, and the Holder
       ----------------                                                        
shall be entitled to receive a new warrant, which shall be dated as of the date
of this Warrant, covering the number of shares in respect of which this Warrant
shall not have been exercised.

   5.  Issuance Date.  The person or persons in whose name or names any
       -------------                                                   
certificate representing shares of Series A Preferred Stock is issued hereunder
shall be deemed to have become the holder of record of the shares represented
thereby as at the close of business on the date this Warrant is exercised with
respect to such shares, whether or not the transfer books of the Company shall
be closed.

   6.  Exercise; Expiration Date.  This Warrant shall expire at the close of
       -------------------------                                            
business on the third (3rd) anniversary of the Exercise Date, and shall be void
thereafter.

   7.  Reserved Shares; Valid Issuance.  The Company covenants that it will at
       -------------------------------                                        
all times from and after the date hereof reserve and keep available such number
of its authorized shares of Series A Preferred Stock and Common Stock free from
all preemptive or similar rights therein, as will be sufficient to permit the
exercise of this Warrant in full and the conversion into shares of Common Stock
of all shares of Series A Preferred Stock received upon such exercise.  The
Company further covenants that such shares as may be issued pursuant to the
exercise of this Warrant and conversion of the shares of Series A Preferred
Stock acquired thereby, will, upon issuance, be duly and validly issued, fully
paid and nonassessable and free from all taxes, liens and charges with respect
to the issuance thereof.

   8.  Dividends.  If after May 7, 1998 (the "Authorization Date") the Company
       ---------                              ------------------              
shall subdivide the Series A Preferred Stock, by split-up or otherwise, or
combine the Series A Preferred Stock, or issue additional shares of Series A
Preferred Stock in payment of a stock dividend on the Series A Preferred Stock,
the number of shares issuable on the exercise of this Warrant shall forthwith be
proportionately increased in the case of a subdivision or stock dividend, or
proportionately decreased in the case of a combination, and the Purchase Price
shall forthwith be proportionately decreased in the case of a subdivision or
stock dividend, or proportionately increased in the case of a combination.
<PAGE>
 
                                      -3-

   9.  Mergers and Reclassifications.  If after the Authorization Date there
       -----------------------------                                        
shall be any reclassification, capital reorganization or change of the Series A
Preferred Stock (other than as a result of a subdivision, combination or stock
dividend provided for in Section 9 hereof), or any consolidation of the Company
with, or merger of the Company into, another corporation or other business
organization (other than a consolidation or merger in which the Company is the
continuing corporation and which does not result in any reclassification or
change of the outstanding Series A Preferred Stock), or any sale or conveyance
to another corporation or other business organization of all or substantially
all of the assets of the Company, then, as a condition of such reclassification,
reorganization, change, consolidation, merger, sale or conveyance, lawful
provisions shall be made, and duly executed documents evidencing the same from
the Company or its successor shall be delivered to the Holder, so that the
Holder shall thereafter have the right to purchase, at a total price not to
exceed that payable upon the exercise of this Warrant in full, the kind and
amount of shares of stock and other securities and property receivable upon such
reclassification, reorganization, change, consolidation, merger, sale or
conveyance by a holder of the number of shares of Series A Preferred Stock which
might have been purchased by the Holder immediately prior to such
reclassification, reorganization, change, consolidation, merger, sale or
conveyance (or, if there are no holders of Series A Preferred Stock at such
time, by a holder of the number of shares of Common Stock which might have been
acquired by the Holder immediately prior to such reclassification,
reorganization, change, consolidation, merger, sale or conveyance upon the
exercise of this Warrant in full and the conversion into shares of Common Stock
of all shares of Series A Preferred Stock receivable upon such exercise), and in
any such case appropriate provisions shall be made with respect to the rights
and interest of the Holder to the end that the provisions hereof (including
without limitation, provisions for the adjustment of the Purchase Price and the
number of shares issuable hereunder) shall thereafter be applicable in relation
to any shares of stock or other securities and property thereafter deliverable
upon exercise hereof.

   10. Fractional Shares.  In no event shall any fractional share of Series A
       -----------------                                                     
Preferred Stock be issued upon any exercise of this Warrant.  If, upon exercise
of this Warrant as an entirety, the Holder would, except as provided in this
Section 12, be entitled to receive a fractional share of Series A Preferred
Stock, then the Company shall issue the next higher number of full shares of
Series A Preferred Stock, issuing a full share with respect to such fractional
share.

   11. Certificate of Adjustment.  Whenever the Purchase Price is adjusted, as
       -------------------------                                              
herein provided, the Company shall promptly deliver to the Holder a certificate
of a firm of independent public accountants setting forth the Purchase Price
after such adjustment and setting forth a brief statement of the facts requiring
such adjustment.

   12. Notices of Record Date, Etc.  In the event of:
       ---------------------------                   

       (a) any taking by the Company of a record of the holders of any class of
   securities for the purpose of determining the holders thereof who are
   entitled to receive any dividend or other distribution, or any right to
   subscribe for, purchase or otherwise acquire any shares of stock of any class
   or any other securities or property, or to receive any other right,
<PAGE>
 
                                      -4-

       (b) any reclassification of the capital stock of the Company, capital
   reorganization of the Company, consolidation or merger involving the Company,
   or sale or conveyance of all or substantially all of its assets, or

       (c) any voluntary or involuntary dissolution, liquidation or winding-up
   of the Company,

then and in each such event the Company will mail or cause to be mailed to the
Holder a notice specifying (i) the date on which any such record is to be taken
for the purpose of such dividend, distribution or right, and stating the amount
and character of such dividend, distribution or right, or (ii) the date on which
any such reclassification, reorganization, consolidation, merger, sale or
conveyance, dissolution, liquidation or winding-up is to take place, and the
time, if any is to be fixed, as of which the holders of record in respect of
such event are to be determined.  Such notice shall be mailed at least 20 days
prior to the date specified in such notice on which any such action is to be
taken.

   13. Amendment.  The terms of this Warrant may be amended, modified or waived
       ---------                                                               
only with the written consent of the Company and the holder of this Warrant;
provided, however, if the holder of this Warrant transfers this Warrant with
--------  -------                                                           
respect to any of the shares purchasable hereunder, this Warrant may be amended,
modified or waived only with the written consent of the Company and the holders
of the Warrants representing at least two-thirds of the number of shares of
Series A Preferred Stock then issuable upon the exercise of such Warrants.  No
such amendment, modification or waiver shall be effective as to this Warrant
unless the terms of such amendment, modification or waiver shall apply with the
same force and effect to all of the other Warrants then outstanding.

   14. Warrant Register; Transfers, Etc.
       ---------------------------------

       A. The Company will maintain a register containing the name and address
   of the registered holder of the Warrant, and if the holder of the Warrant
   transfers this Warrant with respect to any of the shares purchasable
   hereunder, the names and addresses of the holders of such Warrants.  The
   Holder may change its address as shown on the warrant register by written
   notice to the Company requesting such change.  Any notice or written
   communication required or permitted to be given to the Holder may be given by
   certified mail or delivered to the Holder at its address as shown on the
   warrant register.

       B. Subject to compliance with applicable federal and state securities
   laws, as well as Section 17 hereof, this Warrant may be transferred by the
   Holder with respect to any or all of the shares purchasable hereunder.  Upon
   surrender of this Warrant to the Company, together with the assignment hereof
   properly endorsed, for transfer of this Warrant as an entirety by the Holder,
   the Company shall issue a new warrant of the same denomination to the
   assignee.  Upon surrender of this Warrant to the Company, together with the
   assignment hereof properly endorsed, by the Holder for transfer with respect
   to a portion of the shares of Series A Preferred Stock purchasable hereunder,
   the Company shall issue a new warrant to the assignee, in such denomination
   as shall be requested by the Holder hereof, and shall 
<PAGE>
 
                                      -5-

   issue to such Holder a new warrant covering the number of shares in respect
   of which this Warrant shall not have been transferred.

       C. In case this Warrant shall be mutilated, lost, stolen or destroyed,
   the Company shall issue a new warrant of like tenor and denomination and
   deliver the same (i) in exchange and substitution for and upon surrender and
   cancellation of any mutilated Warrant, or (ii) in lieu of any Warrant lost,
   stolen or destroyed, upon receipt of evidence reasonably satisfactory to the
   Company of the loss, theft or destruction of such Warrant (including a
   reasonably detailed affidavit with respect to the circumstances of any loss,
   theft or destruction) and of indemnity reasonably satisfactory to the
   Company; provided, however, that so long as Silicon Graphics Computer Systems
            --------  -------                                                   
   is the registered holder of this Warrant, no indemnity shall be required
   other than its written agreement to indemnify the Company against any loss
   arising from the issuance of such new warrant.

   15. No Impairment.  The Company will not, by amendment of its Certificate of
       -------------                                                           
Incorporation or through any reclassification, capital reorganization,
consolidation, merger, sale or conveyance of assets, dissolution, liquidation,
issue or sale of securities or any other voluntary action, avoid or seek to
avoid the observance or performance of any of the terms of this Warrant, but
will at all times in good faith assist in the carrying out of all such terms and
in the taking of all such action as may be necessary or appropriate in order to
protect the rights of the Holder.

   16. Governing Law.   The provisions and terms of this Warrant shall be
       -------------                                                     
governed by and construed in accordance with the internal laws of the State of
Delaware.

   17. Successors and Assigns.  This Warrant shall be binding upon the Company's
       ----------------------                                                   
successors and assigns and shall inure to the benefit of the Holder's
successors, legal representatives and permitted assigns.  Notwithstanding the
foregoing, the holder of this Warrant may not transfer the Warrant without the
prior written consent of the Company which consent shall not be unreasonably
withheld, provided, however, no consent of the Company shall be required for
          --------  -------                                                 
transfer of the Warrant to a wholly-owned subsidiary or a financial institution.

   18. Business Days.  If the last or appointed day for the taking of any action
       -------------                                                            
required or the expiration of any right granted herein shall be a Saturday or
Sunday or a legal holiday in California, then such action may be taken or right
may be exercised on the next succeeding day which is not a Saturday or Sunday or
such a legal holiday.

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                           [SIGNATURE PAGE TO FOLLOW]
<PAGE>
 
                                      -6-

                               NUMBER NINE VISUAL TECHNOLOGY CORPORATION

                                
Dated:     5/7/98    , 1998    By:   /s/ Andrew Najda
      ---------------             ----------------------------------------
                                   
                               Name: ANDREW NAJDA
                                    --------------------------------------

                               Title: Chairman of the Board and CEO
                                     -------------------------------------
(Corporate Seal)

Attest:


----------------------------
<PAGE>
 
                                      -7-

                                  SUBSCRIPTION
                                        

To:  NUMBER NINE VISUAL       Date: _________________________
     TECHNOLOGY CORPORATION
     18 Hartwell Avenue
     Lexington, Massachusetts  02173
 


   The undersigned hereby subscribes for __________ shares of Series A Preferred
Stock covered by this Warrant.  The certificate(s) for such shares shall be
issued in the name of the undersigned or as otherwise indicated below:


                             SILICON GRAPHICS, INC.


                             By:_____________________________
 
 
                             Print Name:_____________________

                             Title:__________________________

                             Name for
                             Registration:___________________

                             Mailing Address:________________

                             ________________________________
 
<PAGE>
 
                                      -8-

                                   ASSIGNMENT
                                        

   For value received ____________________________ hereby sells, assigns and
transfers unto_____________________________________________________(please
print or typewrite name and address of Assignee) the within Warrant, and does
hereby irrevocably constitute and appoint _______________________ its attorney
to transfer the within Warrant on the books of the within named Company with
full power of substitution on the premises.


Dated:_______________________


                             SILICON GRAPHICS, INC.


                             By:______________________________
 
                             Print Name:______________________

                             Title:___________________________

In the Presence of:


_____________________________
Witness Signature