Max hash question to the better programmers.

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vaporizer
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Max hash question to the better programmers.

Post by vaporizer »

In regular tourney time controls with engine vs engine or even my engine against human(like 2 hours first 40 moves,then second tier 1 hour,then 30 minutes)...or for even longer time controls,like 6 hours,then 3 hours,then one hour( a setting I use for corresp play)....is it best,(as I have read) to use no more than one half the hash MB relative to my system memory Ram?Its my understanding that if I use more than half,it will slow down the search speed of my engine too much and affect the hard drive in some ways.

I have an HP which has from the factory an 8 GB memory Ram.But its also important to note that upon checking,my "available" Ram,it has only 6.88,not 8 GB.So perhaps one half of 6.88GB or one half of 8 GB?

The math would be:

8GB=8192 MB
6.88 GB=7045.12 MB

Then,in theory,one half of 8192=4096 MB
Or one half of 7045=3522 MB

Now,regardless of what is stated in my UCI,should I only use,say a max of 4096 hash,or perhaps 3522 hash based upon my available ram?Oddly enough,my Komodo 8 64 bit UCI states "max 6144 hash".But 6144 MB,of course,is way over what I read as a recommendable hash setting,even for longer(or very long) time controls.

So can anyone help me in this hash question?

And let me attach one additional question:
Now,for "infinite analysis"(not simply long time control game settings),what hash setting now?The 6144 that my Komodo stated?Lower?

Again,I have an older HP AMD phenom 9750 quadcore PC,8 GB memory(new),6.88 GB available memory(now). 750 GB hard drive.


:o
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Harvey Williamson
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Post by Harvey Williamson »

The most you should use is 4096. You can see if this is ok by checking that you are not getting lots of hard disc activity when the engine is running. 4096 should be ok as long as you are not running anything else at the same time. If you are running engine v engine you probably want to try giving each engine 2048.
vaporizer
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Post by vaporizer »

I figured 4096 would be about that.When I mentioned engine vs engine....I really meant it in a different way.What I meant was "my" engine against another engine through corresp chess,not side by side in my same GUI setup.So,in a case like that,still 4096 you think?

Maybe less?Since my "available" Ram is only 6.88GB?
vaporizer
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Post by vaporizer »

In addition,to my post above,my research kind of indicates to go beyond 4096 with infinite analysis and nothing else running on my computer.But i could be wrong.I keep reading that it is important to run the highest hash available,when using infinite settings for several hours over a move....but i'm still not sure of that.
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Harvey Williamson
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Post by Harvey Williamson »

vaporizer wrote:In addition,to my post above,my research kind of indicates to go beyond 4096 with infinite analysis and nothing else running on my computer.But i could be wrong.I keep reading that it is important to run the highest hash available,when using infinite settings for several hours over a move....but i'm still not sure of that.
Don't go above 4096 with the ram u have as the operating system will start writing some of it to your hard drive. I would try 4096 for everything and just keep an eye on the hard drive and check that activity does not increase.
vaporizer
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Post by vaporizer »

Thanks Harvey.Sounds like "sound"advice.I'm no computer expert....but how do you really tell if there is "too much"activity going on or if there is too much hard drive activity?Graphs?Weird sounds coming from the computer?When my Houdini program is analyzing,many times I can hear the computer go up and down in sounds.Kind of like revving my car engine throttle.

Ha ha,maybe I have been making my computer overwork for years and do not know it!But i know that i have been winning 98% of my games in very strong correp.play.

So,I must be doing something right!I have a feeling however,that I was using that Hard drive more times than not!
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