AMD Radeon HD 6950 & 6970 CrossFire Video Card Reviews

AMD Radeon HD 6970 & 6950 – 40nm Cayman

When AMD announced the Radeon HD 6800 series with video cards based on the Barts GPU back in October it was well received by consumers, but the enthusiasts and gamers that wanted more horse power sat on the sidelines. They were waiting for AMD to release the Radeon HD 6900 series based on the new Cayman GPU. Well, that day has come and AMD has officially announced the Radeon HD 6970 and 6950 video cards. The AMD Radeon HD 5870 was AMD’s single fastest GPU for over a year, but that all changes tonight with the release of the Radeon HD 6970. In fact, AMD is done producing all Radeon HD 5800 series cards and once the supply in the channel runs out those cards will be long gone.

Before we get into the details on these new video cards we want to show you the current product lineup for AMD. As you can see, the ATI Radeon HD 5970 is still sitting on top of the product stack. AMD plans on releasing the Radeon HD 6990 (Antilles) in January 2011 and that will replace the Radeon HD 5970 as the company’s flagship dual-GPU video card. The new AMD Radeon HD 6970 is priced at $369 and should compete with NVIDIA’s GeForce GTX 570 video card that retails $350 shipped online. The Radeon HD 6950 has a $299 price tag and it fills the gap between the GeForce GTX 460 1GB and the GTX 570. Notice that AMD calls the Radeon HD 6970 the superior enthusiast GPU, while the HD 6950 is touted as being in a class of its own.

The Radeon HD 6970 has a core clock speed of 850MHz with a memory clock speed of 1375MHz (5.5Gbps). The Radeon HD 6970 has compute performance rating of 2.7TFLOPs (single precisions) and 675GFLOPs (double-precision). The AMD Radeon HD 6970 has 1536 ALUs (stream processors) and that might be a
shock to some people as the Radeon HD 5870 had 1600 of them. AMD says that the new Cayman GPU is so much more efficient that they can do much more with less ALUs. It’s not that the card has 2GB of GDDR5 memory on a 256-bit bus and that the card has a PowerTune TDP limit of 250 Watts. We’ll talk more about AMD PowerTune in the coming pages. The AMD Radeon HD 6970 has 175GB/s of memory bandwidth and that is significantly more than the 153GB/s seen on the ATI Radeon HD 5870 that this card replaces. Notice that the Radeon HD 6970 has 24 SIMDs and 1536 ALUs.

The Radeon HD 6950 has just 22 SIMDs for a grand total of 1408 ALUs and the card operates at a lower 800MHz core clock and 1250MHz on the 2GB GDDR5 memory. It should be noted that AMD is allowing companies to produce 1GB versions of the AMD Radeon HD 6950 if they should choose to introduce a card at a lower price point. The AMD Radeon HD 6950 has 2.25TFLOPs of single precision power and 564GFLOPs of double-precision performance. The AMD Radeon HD 6950 has just 160GB/s of memory bandwidth, but that is still more than the Radeon HD 5800 series had. The maximum TDP for this board is 200W thanks to AMD PowerTune.

Since Cayman has been more or less designed from the ground up to run on AMD’s s next-generation architecture, that means some rather large changes have taken place. Since these changes are rather significant we are going to take a brief look at some of these new design changes on the following page.