Simplified explanation of how the PS4 is twice as strong graphically as the Xbox One
By Mr Tom
member
vgchartz forum
Background Information:
-In today's day and age the GPU is the bottleneck LONG before the CPU. Thus the GPU will be at the center of what is compared.
-
Both consoles use the same AMD 7000 series architecture so they can be directly compared to their desktop/pc equivalent.
-I have extensive experience overclocking and using many of the cards from the 7000 series.
-In my expereince, the 7000 series benefits directly from changes in Core/VRAM speed. This sounds obvious but what I mean is when I overclock my
Amd HD 7970, its in-game performance boost is equal to
((OverclockedCore/OriginalCore)+(OverclockedVRAM/OriginalVRAM))/2.
-Theoretical computational power does not translate directly into gaming performance. For instance a 7970 is FAR more powerful computationally than the Navidia 680, but it is only a little stronger.
-Latency in memory is no where near as important as speed when it comes to graphics cards.
-The most important specs are
CoreClock, VRAMClock, bandwidth, and # of compute units. That is what I will analyze here.
-The Amd HD 7870 is roughly twice as strong in game performance than the Amd HD 7770.
Comparing Xbox One to the HD 7770
The 7770 has:
-10 Compute Units
-1000MHZ Core
-4500 GHz VRAM
-128-bit Bandwidth
The Xbox One has;
-12 CU
-800MHz Core
-2133MHz VRAM
-256-Bit
So first off the Xbox One has 20% less core speed while the 7770 has 20% less cores; thus they cancel each other out. The Xbox One has double the bandwidth so its VRAM should be effectively 4166MHz compared to the 7770's 4500MHz. The ESRAM and the small tweaks to the One's architecture should make up the rest of VRAM difference. Thus as you can see they very easily compare to each other and it is more than fair to say the One effectively has a 7770 in it.
Comparing the PS4 to the 7870:
The HD 7870 has:
-20 CU
-1000MHz Core
-4800MHz VRAM
-256-bit
The PS4 has:
-18 CU
-800MHz Core
-5500MHz VRAM
-256-Bit
So the PS4 seems 10% in the CU department and 20% weaker in the core speed area. But the VRAM in the 7870 is 15% slower. So we are left with a 15% difficency that will easily be made up by the PS4 GPU's special Architectural and HSA improvements to round it off to a 7870.
Other things to factor into the overall performance difference:
-The PS4 has a secondary back-up processor that handles all of the background functions so the main CPU can be used in its entirety. However the Xbox One does not have one, and as such will have to dedicate at least one core to maintaining the 3 OS's.
-The PS4 has access to 7GB of RAM while the One has access to 5GB. This will reduce the size of the textures the One can use, and how many enemies/things can be used/shown at once.