ATI Radeon HD 4770

The Radeon HD 4770 may sound like yet another mid-range graphics card, but there's something special about this one: it's the first consumer card to use a 40nm GPU, namely ATI's new RV740.

Effectively, the HD 4770 is a little sibling to the HD 4870. Not only is its core physically smaller, thanks to the new fabrication process, it's also been pared back to 640 shaders (as opposed to the 800 of ATI's flagship cards) and the RAM bus has been halved in width to 128 bits. It does, however, keep the 4870's 750MHz core clock and 512MB GDDR5 frame buffer.

In our Core i7-920 test rig, that specification allowed the HD 4770 to average a playable 33fps in Crysis at 1,600 x 1,200 with high detail. Even in the challenging high-res Call of Juarez test it scored 30fps. Those scores naturally don't compete with the HD 4870, which scored 42fps and 40fps in the same tests. But, interestingly, they're identical to the results achieved by the HD 4850.

So what differentiates the HD 4770 from that card? Well, for one thing, its smaller, simpler GPU consumes less power - during our tests, total system power consumption peaked at 164W, compared to 175W with the 4850.

But, more significantly, it's also cheaper to manufacture. While the HD 4850 retails in the US for around $150, AMD plans to launch the HD 4770 at just $99 - which could well translate to a UK price below £100 inc VAT.

That effectively makes the HD 4850 obsolete, and sets the HD 4770 against Nvidia's similarly-priced GeForce GTS 250 - a battle it wins, but only on points. Crysis frame rates were the same with both cards, but the GeForce's Call of Juarez score was lower at 24fps.

We suspect the RV740 has more to give. The move to 40nm gives ATI new scope to drop prices and raise speeds in the near future. So it might make sense to wait a while before investing.

But right now the Radeon HD 4770 exceeds the HD 4850's impressive price/performance proposition while undercutting its power demands. For that reason it necessarily takes over as our current favourite mid-range card.

Author: Darien Graham-Smith