AMD Radeon HD 7970 review

Now we come to the crunch then, the performance of this brand new slice of graphical silicon goodness.

It's quick.

Well, pretty quick.

The AMD Radeon HD 7970 has got the Nvidia GTX 580 beat hands down when it comes to raw graphics chomping, pixel-pushing, polygon-smashing performance.

In all of our gaming benchmarks the HD 7970 has the Nvidia card in second place, especially when you look at the particularly demanding Heaven 2.5 and Crysis 2 benchmarks.

With both those benchmarks you're looking at around a 30% improvement over the Nvidia GTX 580.

Those are the best case scenarios though as the performance benefits in the other titles are much less pronounced, sitting between 13% and 20% frame rate improvements.

When it comes to the previous generation, the venerable Cayman-powered HD 6970, things look better still. The HD 7970 posts a 65% improvement over the older card in the tessellation-heavy Heaven 2.5 benchmark.

That's the highest performance increase, but at worst it's around 25% faster. Ideally you'd be hoping for at least half again performance from a new generation, especially a die-shrink, but that can happen if you take things into your own hands.

This is all before you start waving around the overclocking stick then.

And boy, does this chip overclock.

In fact we ran into the limits of the AMD Overdrive software rather than the limits of the hardware itself. We pushed the card all the way up to 1,125MHz on the core clock and 1,575MHz on the memory clock.

With those numbers the performance increase over the GTX 580 and HD 6970 are way more pronounced with the HD 7970 beating the previous generation by up to 80%.

When overclocked too it gives the previous generation of dual-GPU cards, the Nvidia GTX 590 and HD 6990, a good run for their money. The GTX 590 had the highest score of 33FPS while the HD 7970 comes in just behind at 32FPS.

The HD 6990 actually lags behind it with 29FPS.

It's not just all about the raw performance figures though as AMD has made a lot of effort with the power requirements of the HD 7970, especially when running in idle mode, and with the screen off.

The ZeroCore Power technology means when the screen turns off and the machine goes into the 'long idle' state – where the PC is still running but there is nothing being updated on the screen so the panel goes to sleep – there is only a single chip on the card still running.

That chip is there just to tell the PC there is still a card in the PCIe slot and not to worry. The rest of the graphics card turns off completely, even the fan.