With this Atomic version, Sapphire reveals a desire to squeeze out every last megahertz of performance from the core ATI Radeon HD 4890 design. The Sapphire Atomic HD 4890 graphics card is going to be available only in limited numbers, and overclocks the 4890 to its (safest) extremes.
The Sapphire Atomic HD 4890's core clock speed has rocketed from 850MHz to 1000MHz, while the memory clock has gone from 975MHz to 1050MHz. Given the ability of the 1GB of GDDR5 memory to generate an effective speed four times that of the memory clock, that results in a massive 4200MHz.
These figures comfortably outpace all of the competition - only Powercolor has a product that gets close, and that is hobbled in comparison by a slower core clock.
But the Sapphire Atomic HD 4890 isn't simply about raw speed - this version of the 4890 also comes with Sapphire's new Vapor-X technology. A Vapor Chamber has a vaporised liquid coolant (or water, as we one might refer to it) said to bounce backwards and forwards between hot and cold surfaces.
All we can certainly say is that we can see (and feel) that it keeps temperatures down. And it has a similar effect on the sound levels too. For such a powerful card (indeed, even for many a less-powerful too), the Sapphire Atomic HD 4890 is incredibly quiet.
Not that everything is an improvement on the original 4890 - one of the Sapphire Atomic HD 4890's two 6-pin power connectors has been replaced by an 8-pin. This combination is less well supported by PSUs, so check that you're suitably equipped before you buy. Otherwise, the Sapphire Atomic HD 4890 has many of the same specs as the original - the 256-bit memory bus, 800 stream processors, and DirectX 10.1 support. Note that Radeon chips lack the CUDA and PhysX support of the nVidia alternatives.
Given the heavy-duty hardware, you'd expect the Sapphire Atomic HD 4890 to produce improved scores over the original. And indeed it does, notching up an extra 4-6fps at resolutions of 1280x768 and 1680x1050 over a range of titles (Far Cry 2, Left 4 Dead and Crysis Warhead). The gap lessens slightly at even higher resolutions, but the Atomic is nonetheless several frames faster than a stock 4890.
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