Found this PDF on
Driving HPC Performance Efficiency with Heterogeneous Computing posted by Seronx on the AMD blog.
It gives information on 2014 HSA hardware features for the 9000 GPU and APUs . Key is PCIe 3.0 interface (not in later feature lists).
2014 GPU full HSA features: page 10 & 11
GPU compute context switching
GPU graphics pre-emption
Coherent PCIe for discrete GPU >> This was not in later feature lists
Task Parallel Runtime Integration
• Significant and ongoing BW improvements throughout the memory system
• Continue incredible pace of GPU improvements in performance/watt
• Increase sophistication of the GPU so that it becomes a 1st-class citizen of the overall system architecture
• Single unified virtual address space
• Virtual memory support via IOMMU
• Participation in system-level coherency
• Support for context switching
Page 11 has a diagram with the following information. The APU will use a faster memory technology while the second GPU will use GDDR memory, second GPU can be a card or chip.
Memory bandwidth is already known as an issue and
a new memory technology is planned for 2014 AMD APUs. 2013 APUs are using DDR3 with two 64 bit channels. This and the IOMMU that interfaces with memory will need to be the same going forward for game consoles.
This points to a 2014 design; they can not use the Kabini (2 channel DDR3) and customize it for next generation game consoles, they can't use GDDR5 for the main SoC as it's going to be too hot, requires too much drive current and eventually too expensive so a new memory technology which is probably going to be ultra wide DDR4.
T-RAM signs Globalfoundries to develop high density 32nm and 22nm Thyristor-RAM
It appears that T-RAM can be embedded in bulk silicon, this may be the new memory technology used as cache (L2 and maybe L3) in AMD 2014 APUs. ultra wide DDR4 may be a part of this.
This chart below seems to imply that the GPU on the 2014 discrete card (Volcanic Islands) will be as much a part of the CPU in the APU as the GPU part of the APU is of the CPU is in Sea Islands (2013); multi-apu with hypertransport over pci-express "Coherent PCIe for discrete GPU" mentioned above? Is this being confused with the two APU rumors for the Xbox 720?
Is this being confused with the two APU rumors for the Xbox 720? This is the plan for AMD's 2014 full HSA design.
According to one rumor, Sony is waiting till 2014 for a new memory technology and another, the Xbox will have 2 APUs; they both come with 2014 designs. The PS4 could be a 1 APU design and the Xbox APU plus discrete 2014 GPU. That would have the PS4 design first and the Xbox later which matches another rumor.
Before fanboys attack this, I expect multiple SKUs and the QOS mentioned in the above chart also for 2014 takes care of this. There will probably be a bottom end SKU for both that takes the place of the PS3 and Xbox 360 price point with a top end SKU for both that has a second GPU.
I find it interesting that Sony has a Context switching patent and Microsoft has the QOS patent. Both are needed by both consoles.
There has to be more cooperation and gentleman's agreements between Sony and Microsoft this coming generation than ever before as they are sharing the same or much of the same hardware.
I find statements that one or the other is going to be more powerful or one will be missing a core feature to be less than believable. I find the rumor that only the Xbox 720 will have a ARM A5 processor for "Trustzone" less than believable considering Sony's interest in DRM.