DailyTech has posted benchmarks comparing the ATI Radeon HD 2900XTX and GeForce 8800 GTX. FYI, 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. Their 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.

The test system specifications are as follows:
- AMD ATI Radeon HD 2900 XT (745 MHz core, 800 MHz GDDR3)
- AMD ATI Radeon HD 2900 XTX (750 MHz core, 1010 MHz GDDR4)
- AMD ATI Catalyst v8.361 (drivers slated for retail)
- NVIDIA GeForce 8800 GTX (650 MHz core, 1000 MHz GDDR3)
- ASUS P5N32-E SLI (nForce 680i)
- Intel Core 2 Extreme QX6800
- Corsair XMS2 PC2-8500 (800 MHz, 5-5-5-18, 1T)
- Acer X241W
-- It's important to note that the GeForce 8800 GTX is a vendor overclocked board that comes shipped with the 650 MHz core clock (which is still slower than upcoming 8800 Ultra)

I am really surprised with how crappy the performance is for the XTX....This seems really odd as the XT beat the GTS right? It seems that the 1GB of GDDR4 is not doing what they thought it would. I'm sure if they get it to 1200 or so - it will sort itself out. But they'd also need to move the core clock into the 800 range. Well, we will see but WHEN? :-]   It looks like there won't be any Radeon HD 2900XTX cards, at least not on the 14th of May :-(

In other news, AMD has decided to push forward the launch of the Radeon HD 2900 series to May 2nd instead of the original date on May 14th. Products demonstrations and reviews are allowed to appear on that date so it is considered a soft launch. However, AMD is still keeping Radeon HD 2600 and 2400 under wraps until the big day on May 14th. Radeon HD 2900 XT cards will be available from that day onwards for the price of US$399 to be positioned against the GeForce 8800 GTS. The final clocks for Radeon HD 2900 XT stood at 740MHz core and 825MHz for memories.

Update (Apr27): Reading around today, some over excited folk got their wires crossed and claimed AMD would be launching their upcoming R600XT on May 2nd. That's simply not correct – Nvidia is launching the 8800 Ultra on May 2nd at a retail price of at least $999 USD but supply will be very low due to yield and pricing related issues.