Yes, we know; what's the point of a DirectX 11 graphics card when Windows 7 isn't even out yet, let alone there being any DX11 games available? Well, with each version of DirectX being backwards compatible you can of course use one of these new cards with Windows Vista and all your current games.
The ATI Radeon HD 5000 series, then, are the first cards to hit retail from AMD's new Evergreen family of DX11 cards. They're based on a brand new chip codenamed Cyprus, which is built on the 40nm process as pioneered by the HD 4770. For now, two cards will be based on Cyprus; the HD 5870 and HD 5850, the full details of which are below.
As you can see, the HD 5870 has twice the compute power of the previous generation chip as found in the HD 4890 and HD 4870 though it retains the same 256-bit memory bus width and 1GB frame buffer of the previous generation. Accompanying that increase in compute power is a more than doubling of transistors, up from 959M to 2.15BN - a quite staggering number.
The reference card itself will fill two PCI-Express slots with its bulk and is 11inches long so those of you with smaller cases will probably be out of luck. A surprising feature, though, is these cards will be the first to have DisplayPort as standard and instead of this replacing another output, there will be two DVI and an HDMI as well thus the ability to have three monitors from one card.
The HD 5850, meanwhile, is based on the same chip as the top end card but has a few sectors disabled (generally because of manufacturing defects). In this case it equates to two SIMDs (80 strong sectors of stream processors) being disabled along with their accompanying texture units. The GPU and memory will also be clocked a little lower.
The inner workings of the Cyprus GPU are essentially identical to that of RV770, which powered the HD 4870, so if you want an in depth look at that aspect of things then check out that review. In a nutshell, the new GPU adds support for DX11 instructions, angle independent anisotropic filtering, and the new Eyefinity feature that lets one card run up to three monitors and, in later revisions, up to six.
Perhaps the most anticipated aspect of these new cards, aside from the new level of performance you'll be able to get from a single chip card, is they are set to have very low power consumption. For the HD 5870, idle power is said to be just 27W while under load this will rise to only 188W.
Unsurprisingly, these new cards don't exactly come cheap with the HD 5870 demanding 300 of your hard earned pounds. However, the HD 5850 is actually very competitively priced at just £200.
All we need now is for our review sample to actually turn up and we can get on and review the thing for you…