Arasan 20.4.1

[jdart]

I have made a couple fixes in 20.4, available at https://www.arasanchess.org:

1) Fixes to ensure tablebases are initalized before search in UCI GUIs.
2) Fix to output correct TB scores in UCI multi-pv mode.

Also apparently the "vanilla" arasanx-64 executable on Windows was not built properly to support older processsors - this should be fixed now.

And this version has a few opening book updates.

--Jon

[CMCanavessi]

Thanx Jon! Long time fan of Arasan since the stone age or so.

[attakinski]

Tanxs Jon!

[Ponti]

Which version is the best to use with a Ryzen 7 1800X ?

[jdart]

Use the bmi2 version if possible. But the performance differences among the Windows versions are fairly small.

--Jon

[Ponti]

Sorry but...what does "bmi2" mean ? Is it a special compile for Zen processors ?

[AndrewGrant]

BMI2 is known to have some issues on some of the Zen processors.

Just download them all, and choose the one with the greatest NPS, assuming search is deterministic.

[jdart]

BMI2 is a set of instructions available on newer Intel processors (Skylake) and Ryzen. They are supposed to make some chess operations faster, but there are some reports that they have poor performance on AMD chips so for those you may find the popcnt build better. In any case though the differences among the various Arasan builds are fairly small.

-- Jon

[jpqy]

Yes,it's clearly shown in this list that pop compiles run much faster then bmi2 compiles on AMD Ryzen,Threadripper & EPYC systems!

http://www.ipmanchess.yolasite.com/amd- ... -bench.php

JP.