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EXHIBIT 6

# CERTIFICATION OF CHIEF
EXECUTIVE OFFICERPURSUANT TO SECTION 302 OFTHE SARBANES-OXLEY ACT OF 2002

I, David Orton, principal executive
officer of ATI Technologies Inc. (the issuer), certify that:

|1. |  | I
have reviewed this      annual report on Form 40-F of the issuer;
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|2. | Based on my knowledge, this report does not contain any untrue statement of a
               material fact or omit to state a material fact necessary to make the statements
               made, in light of the circumstances under which such statements were made, not
               misleading with respect to the period covered by this report;
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|3. | Based on my knowledge, the financial statements, and other financial information
               included in this report, fairly present in all material respects the financial
               condition, results of operations and cash flows of the issuer as of, and for,
               the periods presented in this report;
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|4. | The issuers other certifying officer and I are responsible for
               establishing and maintaining disclosure controls and procedures (as defined in
               Exchange Act Rules 13a-15(e) and 15d-15(e)) for the issuer and have:
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| | (a) | Designed such disclosure controls and procedures, or caused such disclosure
               controls and procedures to be designed under our supervision, to ensure that
               material information relating to the issuer, including its consolidated
               subsidiaries, is made known to us by others within those entities, particularly
               during the period in which this report is being prepared;
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| | (b) | Evaluated the effectiveness of the issuers disclosure controls and
               procedures and presented in this report our conclusions about the effectiveness
               of the disclosure controls and procedures, as of the end of the period covered
               by this report based on such evaluation; and
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| | (c) | Disclosed in this report any change in the issuers internal control over
               financial reporting that occurred during the period covered by the annual report
               that has materially affected, or is reasonably likely to materially affect, the
               issuers internal control over financial reporting; and
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|5. | The issuers other certifying officer and I have disclosed, based on our
               most recent evaluation of internal control over financial reporting, to the
               issuers auditors and the audit committee of the issuers board of
               directors (or persons performing the equivalent functions):
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| | (a) | All significant deficiencies and material weaknesses in the design or operation
               of internal control over financial reporting which are reasonably likely to
               adversely affect the issuers ability to record, process, summarize and
               report financial information; and
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| | (b) | Any fraud, whether or not material, that involves management or other employees
               who have a significant role in the issuers internal control over financial
               reporting.
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|Date: November 22, 2005 | By: |  | /s/ David Orton
David Orton
President and Chief Executive Officer
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