Radeon HD 6800 speculations, rumours and leaks

We’re getting close to launch

WE’RE A WEEK away from the anticipated launch of the Radeon HD 6800 series and there’s been more than a few leaks over the past 24h and we figured we’d try and collate some of that information into a more easily digestible format. There are still some key features that are missing and of course the all-important price, but apart from that, we seem to have a pretty good picture of what’s coming.

One feature that the new 6800 cards are capable of that none of the previous generation of Radeon cards, nor any Nvidia cards can offer is the ability to daisy chain DisplayPort monitor thanks to the two mini DisplayPort 1.2 interfaces. The cards support up to six monitors this way, although we don’t know what the maximum display resolution will be. All reference cards will also feature a pair of DVI ports – of which one supports analogue output while the other is digital only – and a single HDMI port. It will of course be up to the graphics card manufacturers to decide on which ports to include on their own cards.

Early 6870 boards will use eight layer PCBs, while later on we’ll see cheaper six layer partner boards. The 6850 will use six layer boards as standard, but there’s an option here for “premium” boards which will use eight layers. The 6870 has a max board power above 150W and as such will be fitted with a pair of 6-pin power connectors, while the 6850 will be below 150W and only gets a single 6-pin power connector. Again, the premium boards will most like feature a pair of power connectors for extra overclocking potential.

We’ll also be seeing different coolers on the cards where the 6870 will, at least initially, feature a radial fan and a plastic shroud – see the leaked XFX board picture below – and the premium 6850 cards will use the same cooling solution. However, as always, it’ll be up to the partners to use their own cooling solutions, but the 6850 should ship with a standard axial fan. This suggests a cooler running chip than the 5800 series, something that the leaked slides verifies by stating that Barts draws less power than Cypress.

Although we’ve seen leaked board designs for the 6800 series – such as the one below – with the power regulation circuitry on the front, it’s not guaranteed that this will be the kind of PCB that the partners will use. The simple reason for this is that Barts is pin-to-pin compatible with Cypress and as such you could simply just stick a Barts GPU onto a Cypress board and you have a finished product with zero R&D cost. This will be very tempting for a lot of partners, especially as we’d guess a cheap 5830 PCB will work since it has as many power phases as the 6870 reference PCB. This would, of course, reduce the number of display connectors and we’re not sure how this would impact the CrossFire connectors, as the 6870 reference card only has one, while a 5830 has two.

Some benchmark figures have also leaked, but we’d take them with a pinch of salt for the time being as they have not been verified and we don’t know what the test platform was. In 3DMark Vantage we’re looking at a score of P16270 for the 6870 and P14872 for the 6850 while in 3DMark 06 the 6870 scores 19480 and the 6850 scores 18750. That puts the 6870 above the 5850, but below the 5870 in 3DMark Vantage and about on level with the 5870 in 3DMark 06. The 6850 is faster than the 5830 in 3DMark Vantage and as fast as the 5850 in 3DMark 06.

On a side note, the Cayman cards are expected to be use 10 layer PCBs with the Cayman Pro partner cards set to use eight layer PCBs. Both cards will have radial fans, although again, the Cayman Pro is expected to use simpler cooling solutions on partner boards. The Cayman XT will be fitted with new, faster 6Gbps GDDR5 memory and it will have a power draw below 300W and will feature one 6-pin and one 8-pin power connector whereas the Cayman Pro will use 5Gbps GDDR5 while it has a power draw of below 225W and as such will have two 6-pin power connectors.

It’s still not quite clear where AMD will position the 6800 series, especially with its apparent shift in model numbers and the rumoured re-badging of the 5700 series. As such it’s too early to speculate on pricing as well, although we’d expect AMD to price them higher than the GeForce GTX 460 256-bit cards, but not too much higher. We’re within a week from the actual launch and we’re just going to have to wait and see what AMD’s plans are.S|A

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