Best engine for greater than 8-core SMP system

[FlavusSnow]

I've done a fair share or research trying to find engines that can use more than 8 cores. Crafty and a couple of crafty's offspring are the only world-class engines that I can find for such hardware.

The hardware is there.

Newegg.com pricing:
AMD Opteron 4180 2.6 ghz 6-cores 2@$230 = $460
ASUS KCMA-D8 Dual C32 Mobo 1@$290 = $290
Kingston 8 GB (2x4) DDR3-1333 ECC 2@$166 = $332 (16 GB total)
Harddrive/case/gfx/powersupply allowance $300


Approximate total price: $1,382
And for a little less than twice as much, you can get a 32-core machine at 2.0 ghz

Problem is that these systems would be outperformed ELO wise by a quad core system clocked at a higher frequency...

Anyone know of other engines that can reasonably use this hardware?

[rbarreira]

Problem is that these systems would be outperformed ELO wise by a quad core system clocked at a higher frequency...

Are you sure?

If you look just at raw power, the best quad-cores do a total of around 4*3.5 GHz = 14 GHz

A 12-core at 2.6 GHz would have 31.2 GHz in total which is about twice. With 12 cores the SMP performance shouldn't drop by 50% compared to a quad-core, right?

[FlavusSnow]

You're assuming the engine can use 12 cores. Most only use 8 cores max, which would result in a speedup of only 6.6. For 4 cores, I'll assume a speedup of 3.6:

3.6 * 3.5 = 12.6
6.6 * 2.6 = 17.2

Which would put it at roughly the same ELO when you account for i7's higher single threaded performance vs AMD chips.

So maybe I was exaggerating a little earlier, but still my point is that a $1300 system performs about the same as a $400 system because of the software limitations

[ernest]

Crafty and a couple of crafty's offspring...

Rybka is a crafty offspring?

[rbarreira]

Well obviously I was talking about the engines which *can* use all the cores, otherwise there's no point of course.

Regarding the price, I think you can't really build a $400 system with an Intel i7 CPU, considering that the cheapest i7 is almost $300 not counting motherboard, memory etc (and that's an i7 clocked at less than 3 GHz). More likely it would be at least $700.

[FlavusSnow]

Last I saw Rybka can only use 8 threads... no speedup beyond that. If thats changed, it'd be news to me.

[FlavusSnow]

What engines can use all threads and still get speedup? thats my question, not the cost of hardware.

[ernest]

Last I saw Rybka can only use 8 threads... no speedup beyond that. If thats changed, it'd be news to me.

See http://rybkaforum.net/cgi-bin/rybkaforu ... 19311;pg=1
2 x 6-core

[Vinvin]

I've done a fair share or research trying to find engines that can use more than 8 cores. Crafty and a couple of crafty's offspring are the only world-class engines that I can find for such hardware.

The hardware is there.

Newegg.com pricing:
AMD Opteron 4180 2.6 ghz 6-cores 2@$230 = $460
ASUS KCMA-D8 Dual C32 Mobo 1@$290 = $290
Kingston 8 GB (2x4) DDR3-1333 ECC 2@$166 = $332 (16 GB total)
Harddrive/case/gfx/powersupply allowance $300


Approximate total price: $1,382
And for a little less than twice as much, you can get a 32-core machine at 2.0 ghz

Problem is that these systems would be outperformed ELO wise by a quad core system clocked at a higher frequency...

Anyone know of other engines that can reasonably use this hardware?

Zappa is very good with a lot of cores.
Rybka is very good with 12 cores.

It's already a good start

[FlavusSnow]

Thanks for the link. So it appears a 12T Rybka does search more nodes, but only 50% more than a 4T Rybka... Without time-to-ply there is no way to know if this would actually perform better. My guess is that the 12 core systems would actually perform worse than the 4 core, core i7 at 4.31 Ghz.

KNPS
1620 2x Intel Xeon X5667 4.50GHz x64 12 CPUs Kim Burcham
1331 2x Intel Xeon X5650 4.00GHz x64 12 CPUs Ruben Comes
1013 Intel Core i7 980X 4.41GHz x64 6 CPUs Martin Thoresen
966 Intel Core i7 980X 4.50GHz x64 6 CPUs Roland Acosta
874 Intel Core i7 920 4.31GHz x64 4 CPUs Tsvetan Milchev