| JEMC said: I'm lost when it comes to the specs of the GPUs, but I find those specs a bit odd. Less ROPs and memory bandwidth than even a GTX780? And less texture engines(?) than any ofthe cards of that table? |
Maxwell is a new architecture, it has been tuned for efficiency, real world performance should be a lot better than the paper specs would have you think. Details can be read here but the cliff notes version
First and possibly most important is that they have increased the amount of L2 cache by 8X (from 256KB to 2MB on the GTX 750 compared to the 650) which reduces the amount of memory bandwidth that the card needs.
They have also taken steps to improve the IPC of each core with improvements to scheduling etc that they claim offers 35% increase in performance per CUDA Core. Also they have split the GPU into smaller groups that allows them to work more independantly and allowing them to further improve effeciency by reducing the amount of Synchronization required and increasing the number of special function units.
For an example of how this works out in practive lets look at the existing Maxwell chip that is out now. compare the specs of the
750 Ti
CUDA Cores 640
Texture Units 40
ROPs 16
Core Clock 1020MHz
Memory Clock 5.4GHz GDDR5
Memory Bus Width 128-bit
TDP 60W
Transistor Count 1.87B
GFlops 1306
And
650 Ti
CUDA Cores 768
Texture Units 64
ROPs 16
Core Clock 925MHz
Memory Clock 5.4GHz GDDR5
Memory Bus Width 128-bit
TDP 110W
Transistor Count 2.54B
GFlops 1420
Now on paper it looks like the 650 Ti should out perform the 750 Ti, I mean it has more texture units, more CUDA Cores, more transistors and the same memory bandwidth. However if we compare benchmarks between the two cards
We see that the 750 Ti actually outperforms the 650 by a comfortable margin and using just over half the power to do it on the same 28nm node. Considering that the 880 GTX has more Cuda cores and a higher clock rate than the 780 Ti it should outperform it by an even wider margin in most cases. Now there may be some cases where the 880 may be a little less impressive due to having less ROPs and lower bandwidth such as very high resolutions+AA but we will have to wait and see how that works out. I just hope that price isn't accurate, I was hopeing that Maxwell would push performance per $ up a lot more than that, seems like the price inflation of GPUs will continue (stupid crypto currency driving up AMD's prices removing the price pressure from Nvidia).
Specs do seem pretty dissapointing if the leak is accurate on price.
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