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View Full Version : G71 - GeForce 7900 GTX has only 278 million transistors ?


suburbanguy
03-09-06, 06:25 PM
http://firingsquad.com/hardware/nvidia_geforce_7900_gt_gtx_performance/page2.asp


Its also important to note that NVIDIA manages to pull all this off with fewer transistors than those that were required for the GeForce 7800s G70 GPU, 278 million transistors in G71 versus 302 million for G70. NVIDIA is also quick to point out G71s diminutive (for a high-end GPU) die size of 196mm2. This compares favorably to R580, which boasts a die size nearly twice as large at 352 mm2 and G70 at 334 mm2. With a considerably smaller die, G71 should be even cheaper for NVIDIA to produce than G70, assuming equal yields.


what was cut out of G71 from G70 ? this is perplexing.

Dazz
03-09-06, 06:33 PM
A die shrink will do that as they are able able to have the same amount in more compressed state as such lowers heat and transistor count.

agentkay
03-09-06, 06:43 PM
The core was optimized, check out the [H] review, it speaks a little about what have been done that results in the lower transistor count. IMO, the transistor count/lower temp. is one of the most impressive thing about the 7900. It delivers overall X1900 performance at similar clocks but with 100 million transistors less (and lower temps and more quiet fans).

Sazar
03-09-06, 06:58 PM
Keep in mind the additional trannies in the r580 are used for a variety of other things that nvidia did not introduce into the g71.

Naturally this is a design choice on their part, but there is a reason for the extra trannies.

keith33
03-09-06, 07:16 PM
Most of the benchmarks show the 7900GTX ahead of the X1900XTX by 3 to 4fps. With some optimized drivers in the next month or so, that lead should definately increase. The fact that a high-end performance card is so damn quiet and cool is a huge plus to anyone that doesn't want a heating plant in their room.

Dazz
03-09-06, 07:22 PM
Same can be said for the X1900 also with drivers to better utilise the extra shaders could put it well a head.

agentkay
03-09-06, 07:34 PM
What extra shaders? It has the same amount of shader processors. I dont think they perform all that different. However the ring bus thing is actually quite a bonus since it reduces the performance hit from AA and AF. But still, if you consider the 325mill(?) trannies of the X1800 and what has been added with the X1900 (3 ALU per pipe and around 380mill transistors I think), it kind of shows that the extra ATI features like the Ring-bus memory controller and HQ-AF, and the infamous HDR-AA, dont seem to be all that heavy on the transistor count, at least not as much as the extra ALUs in comparison.

I can see a lot of headroom (tranny wise) for Nvidia on the 90nm process but not as much for ATI, but who knows what the transistor limit actually will be with the 90nm (guessing 400-450mill.) Doesnt surprise me that the ATI rumors were suggesting another die shrink for the R600 though.

Dazz
03-09-06, 07:42 PM
the NV 79xx cards have 24 Texture units & 24 shader units giving a possible 48 shaders however no textures, the ATI X19xx cards have 16 texture and 48 shader units.

agentkay
03-09-06, 07:48 PM
From what I heard, all of the 48 NV ALUs can perform TMU and shader ops. Maybe Im wrong, but the gap in shader heavy benchies is close enough for it being true, at least partly. :p

Dazz
03-09-06, 07:52 PM
Thats due to games relying heavy on textures at the moment even fear and thats where the R580 looses out. Intill more shaders are used the R580 will continue to loose.

bkswaney
03-09-06, 11:12 PM
I would take the G71 over the XTX any day for drivers alone.
Even if the xtx is a little faster at some things the stable nv
drivers and the G71's power is first class. :) (nana2)

SH64
03-09-06, 11:20 PM
From what I heard, all of the 48 NV ALUs can perform TMU and shader ops.
If i'm not mistaken only half of them can do textures (24 MADD + (24 MADD or 24 Texture)).

suburbanguy
03-10-06, 09:40 PM
thanks for the replies & explainations guys :)

MUYA
03-10-06, 10:00 PM
Thats due to games relying heavy on textures at the moment even fear and thats where the R580 looses out. Intill more shaders are used the R580 will continue to loose.
That is pure speculation until we know it with real world apps. The thing while I would love to see more done per clock (theoretically) in terms of PS as with x1900XT..the way to go it seems to keep up with future PS heavy games....coldn't drives also have a major impact on reachingthe full efficient utilization of the extra ALUs etc. Scheduling, optimizing the instrc and data to go through in an organized way so what comes out is recognizable and not have to been thrown away. How much of the pixel processors are being efficiently utilized? I was told that in one dev conference for a green company, that even running latest games, the some pixel processors were running idle...all due to inefficiencies or scheduling issues? So it might not be a question of more PS heavygames...but acombination of all factors

killahsin
03-10-06, 11:55 PM
Thats due to games relying heavy on textures at the moment even fear and thats where the R580 looses out. Intill more shaders are used the R580 will continue to loose.


i find this an interesting quote. so basically what your saying is only games like spore that use procedural shader texturing will make use of the x1900? Bevcause outside of spore ive not yet heard of a game that uses fully procedural texturing. Which would make the whole point moot.