How strong is KataGo with an AMD Threadripper 3990X?
~1x RTX 2060
~1x RTX 2070
~1x RTX 2080
~1x RTX 2080 Ti


I mean KataGo running only on this CPU (no GPUs).

From what I have read, for 2 GPUs, there are only slight improvements for more than 16 real CPU cores. Threadripper would only make sense for using 4+ GPUs (say, 3080 or 3090), in which case networking / storage throughput are more decisive and general acceleration might be far below linear (e.g., 3x for 4 GPUs or 5.5x for 8 GPUs). OC, some programs might have better parallelisation. Cooling is also a decisive factor: much space around each GPU is mandatory. A 2000W power supply might, or might not, be enough.

lightvector wrote about 2 GPUs and KataGo in https://www.lifein19x19.com/viewtopic.p ... 28#p259528:
"you just use both GPUs. [...] if you have multiple tasks instead of just one, you just give both GPUs different tasks in parallel and get a 2x throughput. In an MCTS search, you always have multiple tasks. Different GPUs can evaluate different nodes in the tree. [However, SLI is not useful.]"

goame wrote in https://www.lifein19x19.com/viewtopic.p ... 83#p258983:
"2x RTX 2080 Ti are ~2x faster than 1x RTX 2080 Ti."

Therefore, I consider building a PC with 1x or 2x Nvidia RTX 3080 (on a mainboard with two PCIe x16 slots being at least three slots apart) and a ca. 12 cores AMD cpu (I know, 16 cores would be better, but also a bit expensive).

Is KataGo the only program using multiple GPUs effectively or what other programs also do it well?

Seeing your edit, uhm, I have no idea...

Different question: for your 2x 2080 TI, which CPU do you use and to what percentage is it used under load?

Ryzen Threadripper 3990X ~3.5 TFlops
GeForce GTX 1060 6GB ~4.4 TFlops
GeForce RTX 2060 ~5.2 TFlops

6 core CPU and 33% under load.

This is very interesting.
The 4990X which should be available in the next time, could be as strong as the RTX 2060.
5990X could be like one RTX 2080 Ti.
Maybe it starts to make sense to use GPUs and CPUs when running KataGo?

another source https://www.techpowerup.com/cpu-specs/r ... 990x.c2271
AMD Ryzen Threadripper 3990X - 13,209.6 GFLOPS

GeForce RTX 2080 Ti - 13,448 GFLOPS

3990x = 3 *2080Ti

costs

and besides that, it is not known what the difference will be in a particular application

Thanks. I have got another question on your 2 graphics cards:

Do they run on PCIe 3.0 each at x8?

Now, PCIe 4.0 is available but I cannot find a motherboard with dual x16 (for both graphics cards). Do CPUs not support enough lanes yet?

I'm using this one: https://www.amazon.de/X79A-GD45-Mainboa ... B00704JT42

The MSI webpage does not clarify. According to the manual of your motherboard, slots 1 and 4 support up to PCIe 3.0 x16 and allow SLI. The manual is not explicit about speed in the case of dual use. Implicitly, it suggests x16 for each because slot 4 is not used in single use but allows up to x16, which only could occur in multiple use. The motherboard is for 2nd generation Core i, for which the best CPUs provide 40 lanes, like nowadays I think. Since some lanes are used for storage and ports, I guess that the actual dual use speed is x8 or x16 + x8.

I looked for a too low hanging fruit;) Gigabyte X299X AORUS XTREME WATERFORCE is some motherboard running up to 3 cards each at x16...! The socket is LGA2066, a typical CPU is Core i9-10980XE for a modest €1.000 and TDP 165W. Ok, so in principle it is possible. For more realistic options, one must search more extensively or compromise on 2x PCIe 4.0 x8 speed, losing something between 0% and 20% application speed?

Meanwhile I have learned that chipsets can provide additional PCIe lanes so your motherboard might indeed have 2x PCI 3.0 x16.

kata 1.61 s509 40b 1 thread 9 po vs gtp4zen 9d zen7

4:0

9 playouts > 9 dan gtp4zen nice!

attached 1 sgf (1.sgf)
edit: also 4-0 at 6 playouts but didnt include sgfs, attached two-gtp screenshot

6b 1 playout 1 thread vs gnugo 3.8 default settings (level 10?) 12-0
6b 1 playout vs zen 6 (real program, not gtp4zen) 3k 1-0 as black.
was not very close the 6b policy can probably beat zen6 at a higher level. I was really surprised, I respect zen 6 strength alot.