| Machiavellian said: If this is correct than instead of 12 CU cores averaging out to 1.2 TFlops, the Durango actually is 48CU which averages around 3.8TFlops |
No. What you are saying doesn't make any sense since if AMD could create a GPU that's "48 CU" equivalent, they would have already released it to replace HD7970 to combat the GeForce Titan. Besides that, looking at the leaked detailed specs, there is no "hidden" magic/performance in the 12 CU part that somehow makes it a 48 CU one. That's not how GCN works.
http://www.techspot.com/news/51534-detailed-xbox-720-gpu-specifications-leak-online.html
It's 12 Compute Units with 64 Shaders per unit, for a total number of 768 Shaders/Stream processors operating at 800mhz. The performance level of the rumoured specs for Xbox 720's GPU is at HD7770 level, or 1.2 Tflops. There is no "funny math" of any kind. The GPU, based on rumoured specs is significantly slower than PS4's.
If MS leaked fake specs on purpose or will revise the GPU, then everything changes. However based on the 12 Compute Units and the total GPU memory bandwidth, the GPU is way worse than PS4's. Since GCN 1.0 is what AMD has and their next generation GCN architecture won't be out until 2014, the instructions per clock for Durango's GCN and PS4's part should be very similar. There is no way a 12 CU GCN part with 68 GB/sec memory bandwidth can ever outperform an 18 CU GCN part with 176GB/sec memory bandwidth.
Since AMD's fastest mobile GPU is HD7970M at the moment and that has 20 CUs with 1280 Stream Processors/Shaders, there is no way MS is fitting an HD7970 inside Xbox Durango since such a GPU uses 180W of power on its own. Also, chances are to save on costs, MS is also going with a custom APU like Sony is. Since HD7950/7970 silicon is 365mm2 on its own vs. 212mm2 for Pitcairn (HD7850-7870), the cost and complexity of combining a Tahiti XT (HD7950/7970) chip and an 8-core Jaguar CPU is prohibitive.
