So, how can they use a x86CPU with 8gb of RAM? I understand a x86 CPU can use 8gb of RAM (the 4gb limit was always software based on the PC end), but why didn't they go with a 64bit CPU? If this console is to last another 8 years, I'm a bit confused about them choosing a x86 CPU instead of x64? or am i reading this wrong?
Considering rumours last year of HD6670/7670 style GPU, this is extremely impressive.
1.84 Tflops over 176GB/sec memory bandwidth implies a GPU that's very similar to the HD7970M. You have 1152 Stream Processors @ 800mhz, 32 ROPs, 80 TMUs, 256-bit bus @ 5500mhz GDDR5.
GPU comparision
PS4: 18 CUs @ 800Mhz (1.84 Tflops), 176 GB/sec memory bandwidth
HD 7850: 16 CUs = 1024 SPs @ 860Mhz (1.76 Tflops), 154 GB/sec memory bandwidth
HD 7970M: 20 CUs = 1280 SPs @ 850Mhz (2.17 Tflops), 154 GB/sec memory bandwidth
HD 7870: 20 CUs = 1280 SPs @ 1000Mhz (2.56 Tflops), 154 GB/sec memory bandwidth
The memory bandwidth in PS360 GPUs was crippled exactly in half from comparable PC GPUs. HD7970M is just
5% slower than GTX680M with latest drivers. NV charges $350 more in retail for the GTX680M. Makes sense why Sony went AMD. Going with a desktop chip like HD7950/GTX670 would have raised the power consumption pretty high as a single 1.6Ghz quad-core Jaguar has a TDP of 25W, which suggests a custom 8-core version would use 40-50W. Also, costs were likely a factor here too.
Given that consoles are power consumption / heat dissipation constrained, this was nearly the best possible mobile GPU available from AMD until Q3 2013 when higher end HD8000M parts replace HD7970M.
Overall the GPU & memory subsystem are pretty good. The CPU is less impressive though since even the highest bin Jaguar CPU has clocks of 1.85Ghz. This one is probably binned at just 1.6Ghz. Thankfully modern games are starting to use 6 to 8 cores, which should be good for both PC gaming and console gaming optimizations.
Let's not forget that the Cell was just a single core CPU, with 6 supporting SPE/SPU engines. Those engines were not real stand-alone cores and went mostly underutilized over PS3's life. The main single core CPU (PowerPC based) on PS3 had a worse IPC than Pentium 4 3.2ghz. This was a typical case for PS3's CPU in a game like Killzone 2:
The white areas are all the time where the Cell's SPEs were completely underutilized. 6 rows for each SPE/SPU in a typical PS3 game.
Switching to out-of-order 128-bit floating point / AVX instruction Jaguar isn't going to set the world on fire against quad-core Haswell and future CPUs, but it's still a true 8-core OoO CPU unlike the turds that were in the 360/PS3. The other benefit of switching to x86 is that future PS5/6, etc. will be BC and be able to use modern x86 CPUs going forward for 10-20 years. Let AMD/Intel do all the R&D on high-end chips while console makers focus on games, media, overall console experience.