[wmf]

This "sorry ARM" stuff is mostly just the media's need to turn every story into a horse race. But there is some technical detail here: Facebook said they're not ever willing to use 32-bit and ARM won't have 64-bit for years. Also notice that Facebook's servers are "conventional" 2-socket with lots of DIMM slots, not 1-socket "microservers".

[steevdave]

Fwiw, Freescale has a 64bit ppc processor now... Either way though, until you're able to just drop an ARM processor into a "commodity" motherboard, it won't really see widespread use, aside from cell phones, and other mobile devices. There is also the fact that ARM processors all seem to have the graphics card embedded in the chip.

[wtallis]

Current ARM SoCs have all been built for embedded applications, which is why they integrate things like GPUs and radios.

The next-generation high end ARM core, the Cortex A15, will be the first one that's intended to be suitable for server use: they've added virtualization support, PAE for up to 1TB of RAM, and cache coherency to their bus to support SMP. The server-oriented implementations will be quad-core 2.5Ghz chips, of which you would be able to put at least 4 on a motherboard like this. When they start hitting the market next year, they'll probably all but kill the market for Intel Atom-based servers.

[wmf]

QorIQ is pretty cool, but for whatever reason there's massive hype about ARM servers and zero about PowerPC. Perhaps this is evidence of an information cascade.

If Facebook is already getting custom Intel and AMD motherboards, ARM motherboards should be no problem. (Note that a major undercurrent of Facebook's announcement is that "custom" is actually cheaper than "commodity" at "Web scale".) ARM server chips (Armada XP and Calxeda) don't have GPUs.

[rbanffy]

Why would you want to saddle an ARM processor with all the IBM PC 5150 compatibility that lives in every "commodity" motherboard? What would be gained from obliging ARM processors to have the same external signals as x86's? How would they guess how to properly initialize the various components (something processors depend on processor-specific BIOSes and EFI to do)?

[razzmataz]

I am curious if they would ever look into loongson. It's 64bit and fairly power efficient.

[jacques_chester]

There are other MIPS licensees too.

[razzmataz]

True, but loongson is the first one that comes to my mind. I'm not familiar with the other MIPS licensees or the power consumption of their chips.