Exhibit 23.1 CONSENT OF INDEPENDENT REGISTERED PUBLIC ACCOUNTING FIRM We consent to the incorporation by reference into Registration Statement Nos. 333-76223, 333-83521, 333-57972, 333-74100, 333-89134, 333-114324 and 333-123135 on Form S-3, and Nos. 333-8990, 333-30304, 333-57970, 333-70238, 333-107835, 333-114243 and 333-115596 on Form S-8 of our report dated March 31, 2005, appearing in the Annual Report on Form 10-K of Cray Inc. for the year ended December 31, 2004. DELOITTE & TOUCHE LLP Seattle, Washington March 31, 2005