A year or two ago, ATI would have released its latest technologies on the world in the form of a hyper-fast, high-end graphics card that would have cost a fortune, but with the release of the HD4770 it has changed all that, as not only does this card have a world's first 40nm GPU, it is also aimed at the lower end of the mainstream market.

And it has super-fast GDDR5 memory as well. All this in a card that comes in under the £80 mark.

Because the HD4770 (codename RV740) is built on the 40nm process it has two distinct advantages over its siblings; more dies can be produced from a silicon wafer therefore reducing costs, and because of its smaller size it consumes less power, producing less heat and therefore the clock speeds can be increased.

The HD4770 has 826 million transistors on its new 143.75mm² die compared with the 956 million of its two nearest siblings, the HD4830 and HD4850. It has 640 stream processors, the same as the 4830 but less than the 4850's 800. These processors run at the same speed as the core clock: 750MHz, which is faster than both the HD4830 (575MHz) and the HD4850 (625MHz).

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Although the GD4770 only has a 128-bit memory interface compared to the 256-bit interface of the HD4830 and HD4850, ATI has equipped it with GDDR5 memory (which the HD4890 uses) to get around the shortfall of the interface. The 512MB of Qimonda (IGDV51-05A1F1C) GDDR5 memory is clocked at 800MHz but because GDDR5 doubles the I/O throughput this becomes 3,200MHz effective, giving a very respectable 52.1GB/sec of memory bandwidth.

Surprisingly, given the price point of the HD4770, the cooler is a dual-slot one using a copper heatsink and dual heatpipe design. If someone comes out with a single slot cooling solution for the GPU it would be a killer card to build into a media centre or small form factor PC (the PCB measures just 210mm long) giving this type of PC some pretty good gaming performance at last.

As stated above, the smaller die means less power consumption, so the HD4770 has a claimed rated maximum power of 80 Watts, just over the 75W that the PCI-E slot can supply, so the card comes with a single 6-pin PCI-E power connector.

Sapphire's take on the HD4770 is based on the reference clock speeds but loses the reference design cooler for a much smaller and simpler looking heatsink and fan which doesn't cover the complete PCB as the reference design version does, although it still remains a two-slot cooling solution.

As usual with Sapphire cards the bundle is pretty good: component/TV out cable, DVI-VGA and DVI-HDMI adaptors, 4-pin Molex to 6-pin PCI-E power cable, Crossfire adaptor, Driver and CyberLink DVD suite.

So what's the performance like on this sub £80 card? Quite frankly stunning for the price. To show just what it can achieve we tested at two high resolutions; 1,680 by 1,050 pixels and 1,920 by 1,200 pixels and with all in-game details set to maximum/highest.

Using World in Conflict's built-in benchmark we got an average frame rate score of 45fps at 1,680 by 1,050 and 26fps at 1,920 by 1,200. In FarCry 2 we got an average of 48fps and 43fps at 1,680 by 1,050 and 1,920 by 1,200 respectively.

It's hard to believe, but this little card even manages to produce near playable frame rates in Crysis WarHead at 1,680 by 1,050, where it gave an average of 30fps. Reducing the in-game details to a lower level should produce playable frame rates. When it came to the 1,920 by 1,200 resolution it really struggled, though, producing just 19fps.

ATI's Radeon HD4770 blows the lower mainstream market wide open, offering performance never seen at this price point before. Sapphire's take on it offers a much neater cooling solution than the stock cooler.