AMD Radeon HD6950/6970(Cayman) Reviews

[flyck]

Adding geometry horsepower for high-level DX11 rendering adds die size and increases TDP.

Considering 6950 and 6970 have the same die, same tesselation and only minor differences as in less shaderclusters. i don't understand your comment :-)

but an 6950 ran at 870MHz and slightly higher memory clock than 6970 (so little less core clock and bit more memory bw, 10% less shaders etc) causes a a performance difference of 1-2% and a difference of 80W on average (between 6970 and the oced 6950) makes me wonder what is wrong.

You have your numbers wrong.

HD 6950 PowerTune Max = 200W

"Typical" Gaming Power (whatever that is...) = 140W

So yeah, I AM getting close to 200W which is the upper limit of power tune and basically justifies the methodology.

If that is the case then yes.

[SKYMTL]

Considering 6950 and 6970 have the same die, same tesselation and only minor differences as in less shaderclusters. i don't understand your comment :-)

Ah. Well, I am not shure what reviews you have been reading but here is the rundown.

Basically, the move to VLIW5 to VLIW4 did save ALU space on the die but AMD didn't just use this to shrink the core. Basically, they used the "saved" space and expanded upon it by adding additional SIMD engines. The engines with their associated TMUs, cache, etc naturally take up more die area than the reduction to VLIW4 allowed.

The graphics engine iteself (which contains the fixed funtion units like the tessellator) was cloned so instead of one, there are now two. This also adds to the transistor count.

Finally, there are the GPGPU compute changes that necessitated an additional direct memory access engine be added along with some other bits.

All of this of course added to the transistor count and thus increased overall TDP.