Sapphire's HD 4870 features ATI's brand-new flagship Radeon HD 4800 series chips. The chips 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 that 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 board 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 board.

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.

Given its price, the Radeon HD 4870 isn't pitched against the most powerful of nVidia's cards. It's natural enemy is the good ol' GeForce 9800 GTX, either in standard or overclocked variants. We tested the Sapphire Radeon HD 4870 against a similarly priced MSI GeForce 9800 GTX OC, and the results were very much in the HD 4870's favour. Using our demanding Crysis test, we saw the Radeon board pull further ahead of the GeForce the more we upped the settings.

At 1280x720 and the High Quality setting, there was little between them — but from 1400x960 up to full-HD 1920x1,200, the HD 4870 was 25-30 per cent faster than the nVidia board. At the Very High setting, the difference increased to around 40 per cent. By 1400x960 though, the HD 4870 wouldn't produce a usable framerate in Crysis (while the 9800 couldn't top 25fps at any resolution at Very High setting).