Wilco1: Please show your evidence that shows A7 performed better than Intel's, either through the transistor physics or the architecture ALU layout in the chip. Please don't put out any alleged information that is non-scientific and no basis.
Remember this is 18W for a 3GHz octo core at 40nm. A 22nm C2750 runs at 2.4GHz, uses 20W and cannot achieve anywhere near the same performance (X-Gene should have better than Cortex-A57 performance, while we already know Silvermont is slower than Cortex-A15 clock for clock).
So it looks like Avoton will be beaten by a huge margin on performance and power efficiency despite having the advantage of 2 process generations. Now imagine a next-generation X-gene at TSMC 20nm...
Power8 also has external L4 cache as part of its memory controller which is also off-chip. Kind of a halfway house to HMC.
The power battle is actually going to fought on the I/O side. Intel can dial up the core complexity depending on usage. No reason haswell core cannot be brought down to 1w per core. Cache sizes and execution units are the main variables. I would not change the front end too much as that is more painful to change between variants.
The interconnect is a major power hog. No of rings can be altered as Intel has shown. ARM interconnects tend to be NoCs which actually consume more power than a ring. Interconnects like Bus enhanced NoCs or the swizzle switch from U Mich. do reduce noc/crossbar power. In short In terms of I/o arch, ARM is actually the laggard in terms of power. This will be evident if you do an apples to apples comparison. Intel needs higher I/o throughput and hence you are seeing higher power components. At those throughput levels , I suspect power dissipation is non-linear. We are doing some work on 28nm multi core that shows up some interesting results as you scale up.
In the new atom server parts, you can see the wring not being used and a simpler cross type interconnect used instead. That is probably simpler though I still feel rings are more optimal in terms of power.
Did I read correctly the ARM offering was going to be 18watts (4x4.5)? Not exactly low power. Any anaylsis on building more chassis to house more processors that are less capable from a reliability point of view?
@Rick - the point is that pie is already divided and the ARM is going after a piece that is already covered by Intel, which is already on its 2nd-generation Atom microserver chip before ARM is even out of the gate. Kind of like how the Japanese car makers were already on their 3rd-generation design of hybrid cars before Detroit ever got in the act.
At the same time, it will be interesting to see how it goes, especially when the advantages of ARM disappear with the microcode being less of the function blocks in the total chip, and the power advantage gone ... not to mention all the other server requirement, e.g., 64-bit, IO, cach, ECC, etc. The most ironic outcome would be that they end up with ARM creating a niche and it all ends up coming from Intel on its advanced process.