Sapphire Radeon HD2600 XT

At last we're taking a look at another of ATI's HD 2000-series DirectX 10 graphics chips, thanks to Sapphire's HD 2600 XT. The 2600 XT is a step down from ATI's current flagship chip, the Radeon HD2900XT, but it's aimed at mid-range users who want an affordable solution for everyday graphics and a little bit of gaming.

The HD 2600 XT GPU is manufactured using a 65nm fabrication process, unlike NVIDIA's chip or ATI's high-end chip, allowing it to run cooler and with lower energy consumption. Sapphire's HD 2600 XT is also the first DirectX 10 card we've tested that uses GDDR4 memory as opposed to GDDR3, so not everything is a step down from the high-end HD 2900 XT model.

ATI first implemented GDDR4 in its Radeon X1950 XTX DirectX 9 card and has now brought the technology to its HD 2000-series chips, while NVIDIA continues to run on the tried and tested GDDR3. GDDR4 memory offers a fixed burst length of 8-bits rather than 4-bits in GDDR3, so it can produce the same throughput while using half the frequency of a GDDR3 chip. GDDR4 also has a lower power requirement than GDDR3.

Still, it's hardly revolutionary technology and it will only go so far to improve the performance of the card. In the case of the Sapphire HD 2600 XT we have no direct GDDR3 comparison from ATI. If the HD 2600 XT is aimed at the NVIDIA 8600 GT-based (GDDR3) cards, then it's performance is all right for its target market. However, even with GDDR4, it's still not as fast as cards based on NVIDIA's 8600 GTS chip.

The Sapphire uses 256MB of GDDR4 memory with an effective memory clock speed of 2200MHz, while the core clock speed of the graphics chip is 800Mhz. Both these speeds are higher than the HD 2900 XT, but the HD 2600 XT is restricted to 120 stream processors, rather than 320, and the memory bus is 128-bit, unlike the 512-bit memory bus found on the HD 2900 XT.

The Sapphire HD 2600 XT isn't a high-end performer for 3-D applications, but it does hold its own and it offers other benefits, such as a dedicated video decoder called UVD, which helps take the strain off the CPU when decoding video. This feature is especially useful in PCs that don't have a high-end CPU. In 3DMark06, at default setting (1280x1024, no antialiasing or anisotropic filtering) it scored 5107 while the MSI NX8600 GT scored 4495 and the Gigabyte 8600GTS scored 5703, placing it firmly in the middle. At a resolution of 1680x1050, with antialiasing cranked up to 8x and anisotropic filtering at 16x, it scored a lowly 1719.

In F.E.A.R, we ran it at 1280x960 using maximum quality settings, including 4x antialiasing and 16x anisotropic filtering, which turned in a poor 25 frames per second. Clearly if you're after a high-end gaming experience, even on a 19in monitor, you'll need to go for one of the more powerful cards.

If you're after a performance boost down the track, it's worth noting that the card supports native CrossFire mode and Sapphire has included a bridging cable in the box. The rear bracket has two DVI outputs and a TV-out port. The box includes two DVI to D-Sub adapters and a component adapter cable, as well as a DVI to HDMI cable with native audio support.

The card operates without excessive noise and, unlike the HD 2900 XT, takes up just one expansion slot with its cooler, rather than imposing on the adjacent slot. No power cable is required as it draws all its power through the PCI Express slot.