AMD Radeon HD 6970 & 6950 Debut: Enter Cayman

7 thumbs up

At its core, the GPU codenamed “Cayman” is comprised of 2.64 billion transistors and its die size is roughly 389mm2. If you’re keeping track, Cypress (Radeon HD 5870) was comprised of about 2.1 billion transistors and had a 334mm2 die while NVIDIA’s GF110 is made up of approximately 3 billion transistors.  The actual die size for NVIDA’s part hasn’t been disclosed, however, numbers in the 529mm2 range have been thrown around. 


Cayman GPU High-Level Block Diagram

Here we have a high-level block diagram of the Radeon HD 6900 series GPU, aka Cayman. This chip is different from the previous generation Radeon HD 5800 series GPU in a number of ways. First and foremost, the 6900 series is outfitted with dual graphics engines which help keep the GPU well-fed with data, whereas the 5800 series had one. The 6900 series GPU also employs a VLIW4 (Very Long Instruction Word) design; the 5800 was a VLIW5 design. In its full configuration, the chip has 24 SIMD engines, 96 texture units, 32 ROPs (which have been upgraded from previous generations), a 256-bit memory interface and a number of enhancements to improve GPU compute features.


The Dual Graphics Engines Up Close

Cayman’s dual graphics engines give the chip the ability to process two primitives per clock and the dual-engine configuration offers double the transform and backface cullrate than the 5800 series. Incorporated into the engines are also the chip’s dual 8th generation tessellators which now have off-chip buffer support for high tessellation levels among other tweaks. AMD claims the new tessellators will perform up to 3x better than the 5870. Dual rasterizers allow the Radeon HD 6900 series GPU to process up to 32 pixels per clock.

  
The New Core (left) and Render Back End (right) Designs

The new VLIW4 cores have a 4-way co-issue design and all of the cores have equal capabilities. The VLIW5 cores in the 5800 series had a special “T-Unit” that was more capable than the other four units in the core. AMD claims the new core design offers a 10% improvement in performance per mm2 with simplified scheduling and register management.

The render back-ends, or ROPs, have also been upgraded in the 6900 series GPU. The new render back-ends in the chip allow for coalescing of write ops and they can now handle 16-bit integer (unorm/snorm) ops at twice the rate and 32-bit floating point (single/double component) ops are 2x to 4x faster. The end result is faster anti-aliasing performance that causes less of a performance hit than the previous generation.

Article Index:

1 2 Next
0
+ -

hehe i didn't click the picture to get the article :) my bad. much closer performance this time around, but most games still seem to favor nvidia cards, however, the crossfire beat the sli...i guess it will just come down to your favorite of the 2 companies and whether or not u are running single card, 2-4 sli/crossfire.

0
+ -

MMcCutcheon:

testing them? where are the benchmarks! :) now if ati could get their drivers worked out..

Did you bother to read the article?

 

0
+ -

MMcCutcheon:

hehe i didn't click the picture to get the article :) my bad. much closer performance this time around, but most games still seem to favor nvidia cards, however, the crossfire beat the sli...i guess it will just come down to your favorite of the 2 companies and whether or not u are running single card, 2-4 sli/crossfire.

Exactly...

0
+ -

Very Disappointed , I expected the 6970 to Obliterate the 580, bummerTongue Tied ...But based on what it "turned out to be", its performance and the fact that we are approaching the last days of the holiday shopping season, a more reasonable price would set it in favor of many people and reviews.

0
+ -

They're selling already at NewEgg. (And at a good price point too)

(got to go read the review now)

Edit: Not really anything Earth shattering with these card's release. They look good, but not enough to change my mind. Updated drivers could improve their performance, but the same could be said for the NVIDIA cards too. If either ATI or NVIDIA had a clear performance advantage across the board, it would make it an easier job to choose between them. I think that we have to keep in mind that both company's offerings are at a very high performance level to start and either choice is a good one that exceeds what today's games can dish out.

I still feel comfortable with my prior conclusions, two GTX570's will do well for me and give me good performance until I have a chance to build yet again. (CUDA & Phys-X capabilities being the deciding factor, and I'm not too interested in three screen gaming so far)

So I guess it's time to quit pondering and waiting, and start actually buying the rest of my parts. Smile

Thanks for the excellent review guys,..........

0
+ -

Fantastic review, love looking at new tech.

Some what unrelated question, can i put a 6850 and 6870 togather in crossfire? And how bad will it be bottle necked?

0
+ -

Great review!  I have been waiting for this since they were announced.  I am still having a hard time deciding between Nvidia and AMD.  In the past I always bought Nvidia, but I am really liking what I see from AMD lately.  I think I may just have to give them a shot in the PC I'm building at the moment.  As always you guys are the first ones I found with this review.  I'm not seeing any reason to check any other sites, you guys rock!

0
+ -

@fat, to my understanding, you can crossfire them, but the performance of the faster card will be throttled down to that of the slow one.

Somehow I knew these wouldn't beat out the nvidia 500 series. But I really like the price point of the 6950. Plus, the cf scaling is awesome. Can't wait to see all the manufactures OC models.

Oh yeah love those backplates. Really didn't expect to see that on their 6950, especially at 300

Long cards, though. No love for my storm scout ( I could make it work :P )

Great Review, Dave

0
+ -

humm looks like I'll go with the 570GTX this time around for upgrades. Now all i have to do is wait a bit for the $

0
+ -

That Crossfire performance is remarkable.  Nvidia usually always offered better 2 card scaling.  No more I suppose.

1 2 Next
Login or Register to Comment
Post a Comment
Username:   Password: