Analysis

Hello, I want to ask if hyper-threading is bad for stockfish? I mean, I have a core i7 5960x with 8 cores, I am not sure if run the infinite analysis with 8 cores or increase to 16 for maximum performance.

Thanks for every helpful advice

In my opinion Hyper Threading is bad for all chess programs and engines. Just use your REAL CORES..Goodluck

If you core supports Hyper threading, you will not get any speedup from using more threads than physical cores.

It always sounded stupid to me that we should not use all threads available. After all it's hard to expect that a cpu running at 100% load can't deliver more power than 50% loaded.
Therefore, to convince myself, i've conducted a test of 300 games with Stockfish 5 against itself using cutechess.
Although 300 games are usually not enough to speculate precisely a superiority, they show 4 ht cores on 2 physical cores can't beat 2 cores. The difference was only 12 ELO in my case.
Besides 4 ht cores are able to hit 2.8Mnps while 2 cores can only hit 2M.
There are 40% more nodes analyzed but they did't lead to better moves...

The new Intel core i7 - 5960 Can Execute up to 16 Threads concurrently ..!!!

The flagship Core i7-5960X is a true 8-core processor with a 20MB L3 cache. Intel has never produced such desktop products before. Supporting Hyper-Threading, the processor can execute up to 16 threads concurrently. Its base clock rate is set at 3.0 GHz and its integrated PCI Express 3.0 controller provides 40 PCIe lanes.


So its very useful to use the all 16 Cpu with StockFish

Best Regards & HAPPY NEW YEAR

http://www.xbitlabs.com/articles/cpu/display/core-i7-5960x-5930k-5820k.html

http://www.cruxis.com/chess/manual/index.html
Although the hyper-threads often produce a slightly higher node speed, the increased inefficiency of the parallel alpha-beta search more than offsets the speed gain obtained with the additional hyper-threads.
To give a practical example, it's more efficient to use 4 threads running at 2,000 kN/s each than 8 threads running at 1,100 kN/s each, although the latter situation produces a higher total node speed.
For this reason it's best to set the number of threads not higher than the number of physical cores of your hardware.

@Nathanael Russell wrote:

.......it's best to set the number of threads not higher than the number of physical cores of your hardware.

Correct practice.