Last week, we looked at Sapphire's Radeon HD 2600 XT GDDR4 graphics card, finding it to be very good on the features front, especially for HD video playback, but its real problem was that of value for money as a mid-range graphics card for gaming. You see, AMD's previous mid-range product, the Radeon X1950 PRO, delivered much higher frame rates and therefore a better gaming experience when anti-aliasing was enabled. To rub some more salt into the wounds, NVIDIA's GeForce 8600 GT showed more potential with anti-aliasing enabled and, for the most part, was a faster graphics card, but even that wasn't a match for ATI's Radeon X1950 PRO graphics card. - Bit-Tech

HIS Radeon HD 2600 XT IceQ Turbo Graphics Review

And yes, GDDR4 memory is expensive at the moment and therefore not suited to a mid-range card. However, AMD is keen to push GDDR4 into the mainstream so that the price does eventually come down. This is something that NVIDIA doesn't seem to want to support. At the same time though, AMD also recognises that its partners might want to make GDDR3 versions of the Radeon HD 2600 XT in order to make the cards more price competitive with NVIDIA's GeForce 8600 GT. Today we have one example under the spotlight, namely the HIS Radeon HD 2600 XT IceQ Turbo GDDR3 video card.

We've been a fan of what HIS has done for quite some time, as it was the first ATI board partner to really break the mould of only offering cards clocked at ATI's reference clocks. The company's Turbo series is a range dedicated to offering slightly higher than standard clock speeds out of the box. Additionally, HIS moved away from ATI's sometimes noisy reference design coolers and instead teamed up with the guys at Arctic Cooling to use its VGA Silencer coolers. Cards that use these coolers fall into the company's IceQ series. We've looked at quite a few IceQ cards, and generally the technology doesn't change.

Before we move onto the card itself, it's probably worth having a quick recap over what the Radeon HD 2600 XT is all about. The card uses AMD's RV630 graphics chip, which has around 390 million transistors manufactured using a TSMC 65nm process. Those 390 million transistors amount to 120 stream processors split down into 24 five-way superscalar shader processors that are split into three SIMD's, each with eight shader processors per cluster. Each of these clusters is sent instructions via two sequencers and arbiters inside the chip's Ultra Threaded Dispatch processor.

The chip’s texturing capabilities are half that of R600 and also half what NVIDIA's competing G84 GPU processes every clock cycle. Obviously, the real-world differences between the Radeon HD 2600 XT and GeForce 8600 GT are smaller though, because the 8600 GT's texture units are only clocked at 540MHz, compared to 800MHz on the Radeon HD 2600 XT. The RV630 also outputs only half the number of pixels per clock that G84 does, but when you take the difference in clock speeds into account it's not quite as bad as it sounds. While it's still a sizeable difference, it's not near as large as it could have been.

We set about overclocking HIS's Radeon HD 2600 XT IceQ Turbo graphics card using AMD's the overclocking tool that's built into ATI Catalyst Control Center. After a couple of hours of tweaking and gameplay, we managed to get the card running without stability or image quality issues at 860MHz core and 2120MHz memory. Over the factory set clock speeds, the results aren't that great when it comes to the core clock increase, but the memory clock is reasonably impressive. If you take the core increase over AMD's reference clock of 800MHz, the results are a little more impressive though.

The HIS Radeon HD 2600 XT IceQ Turbo graphics card showed a lot more promise than the GDDR4 based Sapphire HD 2600 XT we looked at last week, but we still don't think it's quite enough to really make a consistent challenge against its competitors. Both the GeForce 8600 GT and the previous generation of mid-range hardware performs better on average when anti-aliasing is enabled. In many of these cases with anti-aliasing enabled, the frame rate delivered by these cards is a playable one, and the same cannot be said for the Radeon HD 2600 XT unfortunately.

The Radeon X1950 PRO is a better buy right now because of the lack of compelling DirectX 10 content available at the moment. However, that could change as soon as the end of the week, when potentially the biggest game of the year is released. Waiting until then would be advisable in our opinion, but if you’re dead set on buying a DirectX 10 card today, both the GeForce 8600 GT and Radeon HD 2600 XT should deliver respectable performance in upcoming DirectX 10 titles. The question is though, whether that DirectX 10 gaming experience will be better than the DirectX 9.0c experience.