Sapphire's HD 4870 is the first graphics card we've tested to feature ATI's brand-new flagship Radeon HD 4800 series chips. Alongside its HD 4850 little brother (reviewed here), these cards are reportedly the first to offer a teraflop of computing power.

Despite sounding like a puppet-based sci-fi TV show, a teraflop is actually a measure of one trillion floating point operations per second. The Sapphire Radeon HD 4870 is boasting 1.2 of 'em (or 1,200,000,000,000 calculations per second). ATI says this allows the 4800 series chips to offer twice the performance of the previous 3800 line – which weren't exactly slouches themselves.

Another advance is the first use of GDDR5 memory. This can exchange data with the Sapphire Radeon HD 4870 at up to 3.6Gbps, much faster than the circa2.2Gbps offered by GDDR3 seen by nVidia's mid-to-high-end range (and ATI's HD 4850).

So, the Sapphire Radeon HD 4870 can work faster with textures and other complex, pre-calculated data, all helping to bump up your framerate. As a first-generation 4800 board, the HD 4870 has 512MB of RAM – but we expect to see models with even more memory for gamers soon.

The Sapphire Radeon HD 4870 is a large full-length graphics card with dual power connectors on the end, so you'll need a large case to accomodate it while it takes up two slots. Sapphire's card is bright red and adorned with a Lara-like pistol-packing brunette - but it's as whisper-quiet as MSI's card.

Other useful technologies include the Unified Video Decoder 2 to tap the Sapphire Radeon HD 4870's GPU for better HD video playback, and HDCP support for playing encrypted Blu-ray Discs.

NEXT PAGE: the Sapphire Radeon HD 4870 battles nVidia's finest, images, and our expert verdict > >

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