Sapphire Atomic HD 3870

Verdict: Vapour chamber cooling arrives.

If you were to step into space without wearing a space suit - for instance, if the computer on board your spaceship was showing signs of acute paranoia and trying to lock you out - you'd get cold very quickly. This is because space is an area of very low pressure, and in low-pressure environments water evaporates rapidly, dispersing your body heat into the cosmos.

In case you're wondering why we're talking about extreme cold while alluding to '2001: A Space Odyssey', it's a pertinent topic to consider before looking at Sapphire's new limited-edition Atomic HD 3870. Sapphire is the first PC manufacturer to make use of vapour chamber cooling to cool a graphics card. If the enthusiasm surrounding vapour chamber cooling is anything to go by, this may be the first of many such coolers to grace the pages of Custom PC. You can read about vapour chamber technology and evaporative cooling here, but what about the graphics card as a whole?

The ATI Radeon HD 3870 hasn't had the most enthusiastic of receptions since its release a few months ago. Even though the £150 Radeon HD 3870 offers higher performance than ATI's high-end Radeon 2900 XT, as we saw in our recent graphics card Labs test, it doesn't have enough power to outperform Nvidia's 256MB 8800 GT.

In an attempt to overcome this, the Atomic has been factory-overclocked. Sapphire has raised the card's GPU from its standard speed of 775MHz to 825MHz, a decent boost of 50MHz. As this overclock applies to the 320 stream processors, it should yield good results. The board's 512MB of memory has also been tweaked from 1.125GHz (2.25GHz effective) up to the rounder figure of 1.2GHz (2.4GHz effective). This increases the card's memory bandwidth from 72.8GB/sec to 76.8GB/sec, which should provide a little more leeway for it to stretch its legs at high resolutions.

This is all well and good, but it takes a lot for a new pre-overclocked graphics card to stand out from the crowd these days. Atomic is Sapphire's new flagship graphics card range, which follows on from the Toxic and Blizzard ranges. This Atomic card not only has an innovative new cooler, but also arrives snugly contained in its own foam-padded metal travel case. The travel case includes orange cold-cathode lights and Valve's Black Box, which contains Half-Life 2: Episode Two, Portal and Team Fortress 2 (click for our complete guide to Team Fortress 2). CyberLink Power DVD 7 and the premium version of 3D Mark 06 are also included.

With such lavish accessories and presentation, we expected a lot of performance from the Atomic - after all, with a price of £160, the card is going head to head with the excellent 512MB GeForce 8800 GT, so we'd expect it to offer at least comparable performance. However, at 1,680 x 1,050, Call of Duty 4 was too much for the Atomic; it delivered a minimum frame rate of 24fps. In contrast, a standard 512MB GeForce 8800 GT scored a minimum of 37fps in the same test, and a £125 256MB GeForce 8800 GT managed a 27fps minimum. In fact, the Atomic only just betters a bog-standard £115 Radeon HD 3870, which scored only 2fps less with a 22fps minimum.

From our 1,920 x 1,200 Need For Speed: Pro Street test, it's clear that something other than the clock speeds of the Radeon HD 3870 is holding back the card. Even with the increased speeds of the Atomic, it wasn't any faster than a standard Radeon HD 3870 in this game. While a minimum frame rate of 28fps is fine, it's hardly stellar. Especially when a similarly priced 512MB GeForce 8800 GT card scored a 36fps minimum.

Obviously, unless Sapphire had somehow travelled into the future and stolen some 2009 graphics card blueprints, there's no way that you'll achieve a playable frame rate in Crysis at full detail settings with any single card.

However, with the graphics settings on High and the resolution set to 1,024 x 768, the card almost returned a decent score of 19fps, only 6fps short of the official playable threshold. The 512MB GeForce 8800 GT, however, managed a much smoother minimum frame rate of 32fps .

As the Atomic came so close to the 25fps cut-off point for a playable frame rate in Call of Duty 4 at 1,680 x 1,050, we were eager to overclock the card further and put the new cooler to the test. Refreshingly, ATI's Catalyst drivers now have a working version of Overdrive, the AMD/ATI overclocking tool. Previous attempts to use this tool have resulted in much swearing and the throwing of many small objects around the CPC lab. Avoid the Auto Tune function, as this sets the core speed of the clock massively too high, resulting in a swift system crash - manual control is still the best option when it comes to overclocking.

Performing the speed tweaking ourselves, we found that the card remained stable with the core speed at 850MHz, and the memory was fine running at 1.25GHz (2.5GHz effective). This provided an extra few frames per second, letting us play CoD4 at the native resolution of a 22in TFT. However, this is hardly a miraculous overclock, even if the Atomic is the most overclockable Radeon HD 3870 we've seen. Even with our overclock applied on top of Sapphire's overclock, there was no noise from the innovative vapour chamber cooler and the small, single-height fan.

The Atomic makes its entrance with a lavish presentation. We like its silver case - even if it's pointless once you've plugged in the card - and we like the accessories and free games too. However, none of these makes the card run faster. At the moment, even this, the fastest Radeon HD 3870 on the market, can't compete frame for frame with Nvidia's 512MB GeForce 8800 GT. However, the vapour chamber cooler is brilliant, providing greater cooling power and giving the single-height HSF the low noise levels associated with a dual-height cooler. It's just a shame that AMD/ATI couldn't have given Sapphire something more powerful than an HD 3870.

You can buy the Sapphire Atomic HD 3870 now, at Novetech for £160 inc VAT

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