250W TDP in a package that size.. as the article correctly states, it's about how many FLOPs you can get inside a rackmount case. that TDP alone is going to mean that you wont be able to put that many in a single case.
a dual socket board, 500W on CPUs, 600W with everything else.. the power supply would have to be something special, but the biggest challenge there would be getting the energy (ala heat) back out of the box..
GPUs have similar TDPs and issues - that's why the HSFs on top of them are so massive (and hence GPUs have a bit of an advantage here - they have the entire PCIE board to fit their cooling hardware on)
finally, 4.5ghz? what the hell? in one clock cycle, a beam of light wouldn't even get half way across the board (EDIT: not chip). branch/cache/TLB misses may literally kill any reasonable performance you might hope to get out of it. intel get around this by having years of market leading research in branch predictors, caching models, etc. and it's going to be no mean feat to match that.
i know IBM aren't exactly new to this game. but AFAIK x86 has always been faster, clock for clock, than POWER.
that said, i hope my concerns are misplaced. i'm hoping intel get some competition in the server room. it will be of benefit to everyone.
Light would travel about 660 millimetres in 0.22 nanoseconds, and the chip is about 25 millimetres on the side, so a beam of light could run a few laps around the chip in one clock cycle, or bounce off the sides 20-30 times. Maybe you wanted to say across the motherboard?
I don't think 4.5 GHz is somehow ridiculous when 3 GHz is routine (and POWER7 was 4.2 GHz). Hundreds of cycles of latency when accessing anything off the chip is now routine - that's the world we live in now. I think that the biggest problem is that IBM is not able to make the investments (especially in semiconductor manufacturing) to match Intel's rate of bringing technology to market. The current POWER7 is a 45-nm device if I remember correctly, and this 22-nm POWER8 is not yet on the market. Intel has been selling 22-nm Haswells for how long now? And of course the POWER7 chips have been up against next-generation semiconductors for most of their life.
EDIT: I see that IBM started selling POWER8 systems a few days ago. That's close to a year later than Haswell, and what's more, this chip is likely to compete against 14-nm processors for most of its lifetime.
Aren't they unique in using DRAM for the lowest level of onboard cache, and therefore have a lot of it since those are just tiny cells that store a charge for a while?
Yeah, starting with the POWER7. POWER8 has 96 MiB of eDRAM (e for embedded).
The Centaur memory controllers also have 16 MiB of eDRAM, max them out at 8 and you get 128 total at L4.
Compared to Intel's current offerings, the L1 data cache and L2 unified cache are twice as big. Don't know about timings, though.
The biggest Intel Ivy Bridge Xeon server CPUs have slightly more transistors (100 million), but on a much smaller die, 31% less area. Look at the ones with 12 and 15 native cores: https://en.wikipedia.org/wiki/Ivy_Bridge_(microarchitecture)... they list at $2336 to $6841.
a dual socket board, 500W on CPUs, 600W with everything else.. the power supply would have to be something special, but the biggest challenge there would be getting the energy (ala heat) back out of the box..
GPUs have similar TDPs and issues - that's why the HSFs on top of them are so massive (and hence GPUs have a bit of an advantage here - they have the entire PCIE board to fit their cooling hardware on)
finally, 4.5ghz? what the hell? in one clock cycle, a beam of light wouldn't even get half way across the board (EDIT: not chip). branch/cache/TLB misses may literally kill any reasonable performance you might hope to get out of it. intel get around this by having years of market leading research in branch predictors, caching models, etc. and it's going to be no mean feat to match that.
i know IBM aren't exactly new to this game. but AFAIK x86 has always been faster, clock for clock, than POWER.
that said, i hope my concerns are misplaced. i'm hoping intel get some competition in the server room. it will be of benefit to everyone.