ATI Radeon HD 2900 XTX video cards feature 1GB of GDDR4 video memory, besting the GeForce 8800 GTX?s 768MB of GDDR3 video memory. GPU manufacturers often wait to set the exact clock frequencies of bins until just weeks before launch. Our Radeon HD 2900 XTX sample was released to board partners in the second week of April, features memory clocked at 2.02 GHz and a core clock of 750 MHz. Physically, the Radeon HD 2900 XTX core is identical to the Radeon HD 2900 XT core. Both feature 320 stream processors, but the XTX differs by bringing GDDR4 to the package.Despite the reference clock speed differences, DailyTech managed to push the ATI Radeon HD 2900 XT up to 845 MHz core and 1.99 GHz memory. Unlike the ATI Radeon HD 2900 XT benchmarked yesterday, the HD 2900 XTX is a 12-inch card geared specifically towards OEMs and system integrators.