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When the Radeon HD 2900XT launched it was considerably slower than Nvidia's Geforce 8800GTX.
It was also noisy and lacked Universal Video Decoder (UVD) hardware, present on the HD 2400 and HD 2600, which offloads high-definition processing onto the GPU.
The core of Radeon HD 3800 is essentially the same as the Radeon HD 2900XT, so there are no big performance increases, but various other modifications make it an interesting design. The first change is a 55nm manufacturing process, down from 80nm, which makes it a smaller and cheaper chip to produce.
The number of transistors is down from 700 million to 666 million, despite keeping all 320 stream processors, and the memory interface is cut from 512-bit to 256-bit. Sapphire's Radeon HD 3870, reviewed here, sits very close to another card from Sapphire, namely the Radeon HD 3850.
Two small points differentiate the Radeon HD 3850 and 3870. First, the Radeon HD 3870 has more, and a faster, memory. Second, it also has a bigger, two-slot cooler to dissipate more heat. As a result the cheaper Radeon HD 3850 is a lot hotter to touch.
The bigger cooler also means the Radeon HD 3870 is clocked higher and can be overclocked further, but other than that all 3800 series cards contain the same technology, features and accessories.
AMD has built its UVD into these new GPUs, resulting in a superb score of 90/100 in the industry standard HD HQV test. Nvidia's 8800GT can score higher but you must tweak its settings first, whereas on the 3850 and 3870 everything is set up by default. This makes the Radeon HD 3870 particularly suitable for those building a high-spec home theatre PC.
Another advance is DirectX 10.1, which brings improved HDR lighting and anti-aliasing. It also introduces Cube Map Arrays - a technique that mimics some aspects of the ray-tracing Holy Grail. It will become usable when Vista Service Pack 1 arrives, but games taking advantage of the technology could take a while.
Radeon HD 3800 cores pass another significant milestone by integrating Powerplay technology, which, until now, was reserved for mobile chips only. Powerplay turns off sections of the GPU that aren't in use, saving power and reducing heat. And combined with new fans, with finely adjustable spin speeds, Sapphire's Radeon HD 3800 cards are quiet.
When just running 2D applications in Windows XP, our test system drew 116W with the Radeon HD 3870, compared to 131W with Nvidia's Geforce 8800GT. With the PC running 3Dmark06 this rose to 218W (224W for the Geforce 8800GT). We measured even lower power consumption when we tested with the Radeon HD 3850. It drew just 109W and 195W respectively.
Gaming performance of the 3870 and 3850 was good. Sapphire's Radeon HD 3850 sits in the same price bracket as many Geforce 8600GTS cards (the previous mid-range, DirectX 10 king of the hill) but the 3850's performance was consistently 50 to 150 per cent faster then that.
And performance of the Radeon HD 3870 was extremely similar to the Radeon HD 2900XT, but slower than the 8800GT.
The card includes a VGA-DVI adapter and an HDMI dongle, so you can connect your PC to a big TV without fussing around with audio cables. You also get some games (Valve's superb Black Box with Episode 2, Portal and Team Fortress 2), a Cyberlink DVD suite and a full copy of 3Dmark06 to benchmark your system.
As with the MSI's 8800GT, Sapphire's Radeon HD 3870 comes highly recommended. Both cards, and even Sapphire's cheaper Radeon HD 3850 (£119), blow away the DirectX 10 cards in our recent group test (PCW Christmas 2007). Their performance is superb for the price. If you must buy a cheaper card, then don't spend more than £40 because everything in between no longer cuts the mustard.
All Graphics CardsTags: Graphics Cards
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