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disolitude said: Your whole post falls appart when you add memory bus bandwidth. 7770/7790 has 128 bit bus...X1 has 256. This + SRAM embed is why Xbox 1 GPU will beat both AMD GPUs in performance despite using DDR3 memory. |
The size of the buss didn't change the performance of a GPU... the bandwidth change.
HD 7770 uses a 128bits @ GDDR5 so only 72GB/s bandwidth... Xbone has a 256bits @ DDR3 so only 68GB/s bandwidth... the Xbone GPU in this scenario (not adding the console optmizations or eSRAM) will have a comparable performace if they run at the same clock but Xbone GPU runs at 200Mhz less clock but have more 2 CUs.
But we are talking ot about CUs or core speed here.
In terms of bandwidth it is really low for a GPU of 7770 power... in fact HD 7770 was a disapointed when launched due the 128bits bus... the 256bits with GDDR5 should be a killing GPU.
72GB/s bandwidth make the HD 7770 be weaker than GPU launched two year before with more bandwidth like:
Just for reference the specs of the GPUs listed.
HD 5870: GDDR5@256bits 153GB/s
GTX 560: GDDR5@256bits 128GB/s
Of course... the HD 5870 have better specs but the GTX 560 not... there are the GTX 570 and GTX 580 over the GTX 560.
