Review AMD Radeon HD 6950 – The Feature-rich, High-end Performer

Nearly two months have passed since AMD introduced the first lineups of their 2nd generation, DirectX 11 cards, the Radeon HD 6800 series. The Radeon HD 6870 and HD 6850 are both aimed at the mainstream market. Radeon HD 6870 currently sells for around US$ 239 and is intended primarily to compete against NVIDIA’s GeForce GTX 460 1 GB. Priced at US$ 178, its “little brother”, the Radeon HD 6850, is a rival of the GeForce GTX 460 768 MB.

Having released Radeon HD 6000 series’ mainstream lineups, it’s time for AMD to fill the high-end segment. Meet the Radeon HD 6950 a.k.a Cayman Pro! As one of AMD’s top-of the-line offerings, the Radeon HD 6900 series has everything the HD 6800 series has, plus some additional features not found on the HD 6800s. Let’s begin our discussion by looking at the technical distinctions between AMD’s latest Radeons.

Specification

	AMD Radeon HD 6970	AMD Radeon HD 6950	AMD Radeon HD 6870	AMD Radeon HD 6850
Codename	Cayman XT	Cayman Pro	Barts XT	Barts Pro
Fabrication Process	40 nm	40 nm	40 nm	40 nm
Transistors	2.64 Billion	2.64 Billion	1.7 Billion	1.7 Billion
Die Size	389 mm²	389 mm²	255 mm²	255 mm²
Core Clock	880 MHz	800 MHz	900 MHz	775 MHz
Stream Processors	1536	1408	1120	960
Texture Units	96	88	56	48
ROPs	32	32	32	32
Memory Type	GDDR5	GDDR5	GDDR5	GDDR5
Memory Size	2048 MB	2048 MB	1024 MB	1024 MB
Memory Clock (effective)	5500 MHz	5000 MHz	4200 MHz	4000 MHz
Memory Interface	256-bit	256-bit	256-bit	256-bit
DirectX Version	11	11	11	11
Shader Model	5	5	5	5
Power Connectors	8-pin + 6-pin	2x 6-pin	2x 6-pin	6-pin
Min Recommended Power Supply	–	–	500 W	500 W
Bus Support	PCIe 2.1 x16	PCIe 2.1 x16	PCIe 2.1 x16	PCIe 2.1 x16

The Radeon HD 6900 series (Cayman) chips are fabricated with the same 40nm process used to manufacture HD 6800 graphics chips (Barts) and the previous HD 5000 series. The transistor count, however, is a different story. As much as 2,64 billion transistors are embedded in each Cayman wafer, increasing the physical size of the chip to 389 mm2.

Additionally, the HD 6900 series comes equipped with larger on-board memory of 2 GB, which should give the corresponding graphics card some degree of advantage over the Radeon 6800 series with its 1 GB memory. The extra amount of frame buffer could come in handy in demanding scenarios, such as Eyefinity gaming where the resolution may go to 5760×1080 or even higher.

AMD Radeon HD 6900: Positioning

As shown by a slide from AMD’s press release above, the Radeon HD 6950 goes head on against the GeForce GTX 570. There’s a good chance that the HD 6970 will perform better than its rival, but that remains to be seen. Oddly enough, the Radeon HD 6950 is described as having “a class of its own”, positioned directly a step below the Radeon HD 6970 and GeForce GTX 570. One can therefore assume that the Radeon HD 6950 should be slower (and cheaper) than the GTX 570 which currently retails for around US$ 349.