| thismeintiel said: Well, a couple of them are MS biased, so they may just be saying it will close the gap of the GPUs. However, if they are correct, they still don't take into account that the PS4 is supposed to have its own "secret sauce." So, there would still be a gap. It'll probably be like his gen, only the PS4 will be easier to develop for, so more devs can easily take advantage of it. |
If this so called "secret sauce" was so effective, why wouldn't PCs have a 3rd type of component that alleviates CPU/GPU workload with this "secret sauce"? For example, we'd have the GPU/CPU and some "helper module" that speeds up graphics and it could be plugged into the PCIe slot on the PC.
HD7850-7870 level of GPU delivers 10-20 fps more in modern games compared to HD7770Ghz. When consoles generally target 30 fps, this type of GPU performance difference is huge.
Not to mention, people forget that for the GPU to work fast, it needs a lot of memory bandwidth. If you take the rumored level of performance ~HD7770Ghz in Xbox 720 that normally has 4500mhz GDDR5 over 128-bit bus and replace GDDR5 with DDR3-2133mhz over the same 128-bit bus, your GPU's memory bandwidth will fall from 72GB/sec to just 34 GB/sec!!! Guess what happens? Your GPU performance will fall 40-50% with this reduction in memory bandwidth.
This likely explains why MS is going to use eSRAM/eDRAM for the GPU because 8GB of DDR3 is going to be shared with the GPU (i.e., the GPU is going to be severely memory bandwidth bottlenecked).
In simplest terms, you can take a 1.2Tflop GPU and compare it to a 1.84Tflop GPU on the same GPU architecture, but if the 1st GPU's memory bandwidth just got neutured by DDR3, the performance of that GPU will drop like a rock! Effectively, you are no longer comparing a 1.2Tflop GPU to a 1.8Tflop one because the former GPU can't work at full capacity any longer as it's memory bandwidth bottlenecked.
Example -- GT 640's Floating Point performance is fixed but look at the dramatic effect of swapping out DDR3 for GDDR5 on actual gaming performance.
GT 640 DDR3 = 46 VP
GT 640 GDDR5 = 68 VP (+48% faster) by just swapping out DDR3 for GDDR5.
http://alienbabeltech.com/abt/viewtopic.php?p=41174
On paper, things are looking MUCH worse for the Xbox 720's GPU. Not only is the GPU's floating point rumored to be 50% less than that of PS4, but the actual memory subsystem that feeds the GPU is dramatically inferior to PS4's rumored 4GB GDDR5 setup. The performance difference between an HD7770Ghz DDR3 and an 85% HD7870 GDDR5 is going to be more than double in graphical capability, not 50%, because memory bandwidth is required to keep the GPU working at full capacity (specifically the memory bandwidth feeds the GPU's ROPs).
* The Render Output Unit, often abbreviated as "ROP", and sometimes called (perhaps more properly) Raster Operations Pipeline, is one of the final steps in the rendering process of modern 3D accelerator boards. If you neuter GPU's memory bandwidth, you neuter the ROPs and thus the final stage in the graphical rendering process stage. It's like putting Toyota Prius tires on a 700hp rear-wheel drive supercar. 32MB of eSRAM is not going to be the answer to this problem because it's not sufficient enough in size.
