Not to be out done, ATI announced its mid-range competitor for the GeForce 7600 GT on the same day as NVIDIA announced its new part. However, ATI didn't have availability on day one - we're expecting them to be available in about a week or so and they'll hopefully ship on time with the usual suspects like Sapphire announcing parts the day they're available to purchase.
The Radeon X1800GTO is essentially a crippled R520 - it has the same eight vertex shaders, but only three of the four quads of pixel shaders are enabled. This means that there are only twelve functional pipelines along with twelve pixel output engines. The card comes with 256MB of memory connected to R520's 256-bit memory interface (eight 32-bit channels) running at 990MHz DDR. Incidentally, the X1800GTO's core speed is the same as the Radeon X1800XL's, too.
At a glance, the Radeon X1800GTO looks exactly the same as the Radeon X1800XL from an aesthetic view point. Virtually everything on the board is the same, except for some subtle differences in the power circuitry next to the 6-pin supplementary power adapter - there is an additional inductor, making a total of six.
There are two dual link TMDS transmitters embedded in R520, meaning that the card has support for two huge TFT monitors each capable of running at resolutions up to 2560x1600. There is also a VIVO connector on the back, along with ATI's Rage Theater chip located underneath the heatsink.
With a feature set like that, these cards can't be cheap to produce and the die size is a testament to this fact. R520 is around 321 million transistors packed into a 288mm² package - in comparison to G73, it's well over twice the size. However, this is another one of a growing number of dead-die SKUs coming from ATI in the last six or seven months.
We're not sure how many of these GPU's have damaged pixel pipeline quads and whether ATI is just crippling Radeon X1800XL's in order to get rid of inventory that it can't sell. We guess that time will tell and a large sample of retail products will determine whether the Radeon X1800GTO is unlockable or not. Of course, ATI may decide to hard-lock the Radeon X1800GTO's pipeline configuration with a hardware modification but we're not sure what will happen at this time.
The cooler / form factor: The cooler is the same one that was installed on the Sapphire Radeon X1800XL, and also the Radeon X1800XL reference card too. You'll remember that the Radeon X1800XL operated at its higher speed setting more often than not, meaning that the card is very loud in operation. The worst thing about the cooler is the fact that the temperature threshold for switching to the higher speed setting is relatively low in comparison to the idle temperatures meaning that there is a frequent change of pitch that verges on a major annoyance when gaming. There were times when we had a sudden urge to jam a pen into the fan - that wouldn't do the card any good though.
Despite the reduction in the number of quads being used, the Radeon X1800GTO still runs hot to the touch. Hopefully, ATI's board partners will steer away from the cooling solution on this card - the frequent change of pitch is annoying enough to leave a bad taste in the mouth. It could also prove to be even noisier when two Radeon X1800GTO's are running side by side in CrossFire mode. X1800GTO CrossFire will not require an external dongle or a special CrossFire edition master card either, when ATI releases Catalyst 6.5. Another thing to note is that the card is considerably larger than the GeForce 7600 GT and requires supplementary power, too.