HIS Radeon HD 2600XT iSilenceIII

We’re so accustomed to noise in the Lab that we’re often taken aback by its absence. We knew HIS’s new Radeon HD 2600XT would be quiet, thanks to the factory-installed Zalman iSilenceIII, but it still surprised us.

The card’s modest performance with 3D games (at very high resolutions) was no surprise at all. It came from the factory with a core clock speed of 800MHz and its 256MB of GDDR3 memory set to 700MHz (the GPU has a 128-bit memory interface). The 2600XT mustered just 20 frames per second with FEAR at 1920x1200 and only 27.7 frames per second with Quake 4.

The HIS Radeon HD 2600XT’s performance looked much better when we dropped our resolution demands to 1280x720, which might be all you need if you’re plugging your home-theater rig into a big-screen TV or a video projector. Reducing the card’s workload resulted in a doubling of performance on many of our tests.

Zalman’s cooling apparatus consists of a heatsink, two heat pipes, and a large array of aluminum fins on the back of the card. The extra hardware doubles the thickness of the card, compared to AMD’s reference design, but you shouldn’t have a problem fitting at least one inside a typical HTPC case. Incidentally, Zalman’s device cools only the GPU; heat dissipates via individual heatsinks attached to each of the four memory modules.

The presence of AMD’s ATI Avivo HD—a unified video decoder for Blu-ray and HD DVD playback—is another feature that renders this card more appropriate for home-theater use than straight-ahead gaming. This dedicated circuitry in the GPU offloads much of the video-decoding chores from the CPU (a feature that’s curiously missing from AMD’s top-shelf part, the Radeon HD 2900XT).