With a slightly higher GPU clock, the Radeon HD 6970 has almost exactly the same processing power as the Radeon HD 5870. However, it gives higher triangle throughput and has a higher filtering rate. The good news is that the Radeon HD 6950 is not as significantly cut down in comparison to the Radeon HD 6970 as the Radeon HD 5850 was in comparison to the Radeon HD 5870.
The stock Radeon HD 6900s
For this test, AMD supplied us with a Radeon HD 6970 as well as a stock Radeon HD 6950. The two cards are identical as you can see:
These two new Radeons share the same cooling system, the same PCB and the same power stage. There are some small differences here but they’re purely revision and manufacture details – the two PCBs seem to have been made in different factories. It is however possible that the Radeon HD 6950s sold in stores, especially once the first lots have been sold, will be slightly modified as they obviously don’t require such a sturdy power stage. Moreover, they only have two 6-pin power connectors against 8+6 for the Radeon HD 6970.
In addition to using very fast GDDR5, made by Hynix and certified at 6 Gbps or 1.5 GHz for commands and 3 GHz for data, AMD has gone for no less than 2 GB by default on the Radeon HD 6900s.
For the rest, we’re looking at a standard AMD design with a blower fan and a vapour chamber. Like the Radeon HD 5870 but in contrast to the Radeon HD 5850, an aluminium plate covers the back of the PCB.
In terms of connectivity, AMD has gone for the same set-up as it introduced with the Radeon HD 6800s, namely two DVI Dual-Link outs, an HDMI out and two mini-DisplayPort outs. Tri and quad CrossFire X is supported via two dedicated connectors. Besides these, AMD has integrated a small switch to launch a backup bios. The user can flash the first bios but the second is protected, which means you can fall back on it if there are any problems following an update.
The maximum authorised level of energy consumption is fixed at 250W for the Radeon HD 6970 and 200W for the Radeon HD 6950. If the GPU monitoring system records energy consumption over this limit, it gradually reduces the clock via the PowerTune technology. AMD says however that it has fixed the limits of these cards so that this protection doesn’t kick in during the most demanding games and under the most difficult circumstances, namely with a GPU that has high leakage that is in a very hot environment.
You can modify the energy consumption limit in the Catalyst Overdrive panel. AMD allows you to adjust it between –20% and +20%, or between 200 and 300W for a Radeon HD 6970. Reducing it allows you to limit energy consumption and noise levels in gaming in the most demanding situations, while increasing it means you’ll have a bigger margin for overclocking, without which increasing the clock would actually change nothing if the GPU were still to be limited in terms of the amount of power it could draw.