Results Analysis

The HD 6790 1GB, unsurprisingly, slots neatly between the ageing HD 5770 1GB and newer HD 6850 1GB in AMD’s performance line-up. The larger 256-bit memory interface does help the HD 6790 1GB in some circumstances, though, enabling it to perform closer to the HD 6850 1GB in some situations.

In Dirt 2 at 1,680 x 1,050 with 4xAA, for example, the HD 6790 1GB’s minimum frame rate of 52fps is the same as that of the HD 6850 1GB, although its average frame rate of 59fps is much lower. However, this is still a long way behind the minimum frame rate of 68fps achieved by the GTX 550Ti, the HD 6790 1GB’s price-point competitor, in the same test.

In Black Ops the HD 6790 1GB again drops in between the HD 5770 1GB and HD 6850 1GB, but the fight between the GTX 550Ti 1GB is much closer. The HD 6790 1GB comes out on top, but the margin of victory is small; at 1,920 x 1,200 with 4x AA its minimum frame rate of 72fps is just 1fps higher than that of the GTX 550 Ti 1GB.

In the ultra-demanding Arma II, though, the HD 6790 1GB stomps all over the GTX 550Ti 1GB. At 1,680 x 1,050 with 4x AA the HD 6790 1GB produced a minimum frame rate of 27fps; 17 per cent quicker than the GTX 550Ti in the same test. This dominance is impressively repeated right up the resolution scale.

The HD 6790 1GB again performs well in Battlefield: Bad Company 2. Despite losing out with a minimum frame rate of 22fps at 1,680 x 1,050 with 4x AA to the GTX 550Ti 1GB’s 26fps, the HD 6790 1GB performs just as well at 1,920 x 1,080 with 4x AA, matching the GTX 550Ti 1GB’s minimum frame rate of 22fps, and surpassing its average frame rate.

While the HD 6790 1GB’s twin 6-pin PCI-E power connectors indicate its extra thirst for power, our review sample’s peak power consumption was only 8W more than a stock HD 6850 1GB. Clearly then the HD 6790 1GB isn’t using too much extra juice. The peak temperature of 45°C under load is reasonable too, although the HD 6790’s power consumption and thermal performance will largely be down to which partner's card you buy.

Overclocking

Tinkering with the card’s clock speeds, we managed to push the core clock to a stable 960MHz, a tidy 14 per cent increase over the stock speed. We also managed to push the memory clock to 1200MHz (4.8GHz effective), an equally impressive 14 per cent overclock. Of course, this is using our ‘stock’ HD 6790 1GB; different partner cards will overclock more or less, depending on PCB designs and different coolers, as well as the GPU luck–of-the-draw.



Our overclock saw a tidy improvement in Dirt 2 at 1,920 x 1,080 with 4xAA, with the minimum frame rate climbing 10 per cent from 48fps to 53fps. Arma II also saw a sizeable improvement, with the minimum frame rate climbing from 20fps to 24fps. However, even with our overclock, the HD 6790 1GB failed to convincingly overhaul the HD 6850 1GB; a card just £15 dearer. The HD 6790 1GB's lower ROP count is likely the cause.

Conclusion

Whether the HD 6790 1GB goes all HD 5830 1GB on us and largely disappears after three months, or whether it’s a genuine long term introduction into the AMD line-up isn’t clear at the moment. What is apparent, though, is that the HD 6790 1GB has the better of Nvidia’s GTX 550Ti 1GB in the vast majority of circumstances. While the GTX 550Ti is faster in Dirt 2, in every other game we tested the HD 6790 1GB was as fast or faster, particularly at higher resolutions such at 1,920 x 1,080.

Of course, even then the HD 6790 1GB is comparatively under-powered in comparison to more auspicious competition from the likes of the GTX 560Ti 1GB, or even the £15-20 dearer HD 6850 1GB. As such, we’d still recommend that potential buyers dig deeper and grab themselves a slightly more expensive graphics card that won’t show its age quite so soon.

For those on a very limited budget, though, the HD 6790 1GB offers an attractive half-way house between AMD’s low-end and mid-range that betters the Nvidia competition. We can't reccomend spending this little on a GPU, as a little extra cash nets you a fair bit more performance, but if you absolutely can't spare more than £115, then the HD 6790 1GB is the card to get.

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Score Guide