128-core AMD server

[Leo]

Some benchmarks (Stockfish 8, 16G hash):

32-core dual Opteron (2xOpteron 6376, 1/4 of the AMD server box, Linux):
26.3M nps

24-core dual Opteron (2xOpteron 6344, Linux):
21.8M nps

dual Xeon 2670 (16 cores, Linux):
24.0M nps

i7-6900k (8 cores, Windows):
14.08M nps

What about the argument that its time to depth that matters?

[Leo]

Rates in my area ramp up with usage and I have once in a while hit their "super overcharge now we're really serious" rate level, whatever they actually call it.

I am planning to get solar panels on the house next year.

--Jon

I have a 15 amp breaker that kept tripping. It was hot to the touch. I now have to wait until I can hook up the computer to 20 amps.

[jhellis3]

What about the argument that its time to depth that matters?

TTD is a useless measurement for LazySMP.

[Adam Hair]

Rates in my area ramp up with usage and I have once in a while hit their "super overcharge now we're really serious" rate level, whatever they actually call it.

I am planning to get solar panels on the house next year.

--Jon

I have a 15 amp breaker that kept tripping. It was hot to the touch. I now have to wait until I can hook up the computer to 20 amps.

Have your electrician check for a loose connection also. There could be a problem where the wire connects to the circuit breaker (small possibility) or where the circuit breaker plugs onto the electrical panel busbar (greater possibility). It is doubtful that you have a large enough overcurrent to cause the circuit breaker to be hot to the touch.

My guess is that the connection between the breaker and busbar is failing.

[Leo]

I have read over and over that a powerful 8-16 core machine will defeat a 32-64 core machine. After 16 to 20 cores it scales very badly. Has something changed or is this still true?

[Leo]

Rates in my area ramp up with usage and I have once in a while hit their "super overcharge now we're really serious" rate level, whatever they actually call it.

I am planning to get solar panels on the house next year.

--Jon

I have a 15 amp breaker that kept tripping. It was hot to the touch. I now have to wait until I can hook up the computer to 20 amps.

Have your electrician check for a loose connection also. There could be a problem where the wire connects to the circuit breaker (small possibility) or where the circuit breaker plugs onto the electrical panel busbar (greater possibility). It is doubtful that you have a large enough overcurrent to cause the circuit breaker to be hot to the touch.

My guess is that the connection between the breaker and busbar is failing.

Thanks for the info.

[jhellis3]

I have read over and over that a powerful 8-16 core machine will defeat a 32-64 core machine. After 16 to 20 cores it scales very badly. Has something changed or is this still true?

It was never true? This has more to do with clock speed, heat generation, and power consumption than any sort of scaling issue.

Generally, the more cores per chip the lower the base and boost clocks because you can only dissipate so much heat per mm^2, unless you want to move to water cooling or something more exotic.

But the idea that more cores are somehow inherently bad is just bullshit. Are there diminishing returns, yes. Does performance per dollar drop drastically, yes. But more nodes searched at higher depths will always be better than nothing (provided equal clocks).

[jwes]

What about the argument that its time to depth that matters?

TTD is a useless measurement for LazySMP.

So you're saying that LazySMP finds better moves at equal depths rather than finding the same move faster.

[jdart]

Arasan scales quite badly on 32 cores, at present. It is on my to-do list to look at soon.

But other engines do better: Stockfish for example.

Crafty also uses multiple cores efficiently and can hits amazingly high NPS, but I haven't tried it on this 32 core box.

--Jon

[Dann Corbit]

Arasan scales quite badly on 32 cores, at present. It is on my to-do list to look at soon.

But other engines do better: Stockfish for example.

Crafty also uses multiple cores efficiently and can hits amazingly high NPS, but I haven't tried it on this 32 core box.

--Jon

Texel scales brilliantly