Would having a faster hard drive benefit in computer chess?

[ChessAddict]

Just wanted to ask if having a faster hard drive would have any benefits in increasing performance in computer chess? Also is there anything else i can do to optimize my computer? Thanks.

[gerold]

Just wanted to ask if having a faster hard drive would have any benefits in increasing performance in computer chess? Also is there anything else i can do to optimize my computer? Thanks.

Transposition tables speeds up chess programs searches.
A lot of ram will help. The hash can be set as high as the
hd will stand without causing a slow down on it.

If you have Vista it is loaded with stuff you may not need.
Just don.t mess with drive D. if you have hp.computer.

[ChessAddict]

How much hash should i use for 1min-5min blitz games?

[M ANSARI]

1 minute ... 32mb has is more than enough ... at 3 min ... I would use 64mb ... at 5 min I would use 128mb. Actually hash size should be directly related to how fast your computer is. The faster your computer is and the more cores you have ... the more hash data you will produce at a given time. The idea is to have the hash size where it will not be filled up at the maximum think time of any given move during the course of the game.

[bob]

1 minute ... 32mb has is more than enough ... at 3 min ... I would use 64mb ... at 5 min I would use 128mb. Actually hash size should be directly related to how fast your computer is. The faster your computer is and the more cores you have ... the more hash data you will produce at a given time. The idea is to have the hash size where it will not be filled up at the maximum think time of any given move during the course of the game.

Those are way low.

The idea is

#entries = NPS * time_per_move * fraction

fraction is what percentage of the nodes are stored in the hash table. If a program probes/stores in the hash table, fraction = 1.0, for a program like crafty that does not store in the hash table, fraction = .25 is a good starting point.

For 1 minute searches, given good hardware, crafty would need this:

bytes = 6000000 * 60 * .25 * 12

6M nodes per second is what I get on my core-2 duo (2.0ghz) laptop, so it is not that exotic. I ran at 24M /sec in the last CCT...

the 12 comes from 12 bytes per entry in Crafty.

so for 1 minute searches, optimal would be 1 gigabyte. That's why I said your numbers are _way_ low...

[jwes]

The times were per game, not per move, so the hash sizes are only somewhat low.

[ChessAddict]

Is there a way to tell if your hashtables are filling up too much or too fast? I know there are times when my engine is playing the line will stay at almost 0.00. and there after my games will be mostly drawish. Thanks.

[bob]

The times were per game, not per move, so the hash sizes are only somewhat low.

Then the numbers given are worthless and can not be used to set the hash size unless you know something about the time allocation the program uses. In a 1 minute game, crafty could use 5 seconds on a normal move, move than that if it fails low, and on a long ponder while the opponent is in a deep think it could use even more.

I don't play 1 minute games. I do sometimes play 1+2 or 2+ type games, but then the +increment changes things a lot...

[Mike S.]

the 12 comes from 12 bytes per entry in Crafty.

Is 12 bytes a typical value, for one position in hash? In other words, if I don't know what an engine uses, is it the best assumption?

About hash size and speed: I understand that in theory, due to the hash concept, the total size of the hash table doesn't matter for the access speed. But I roughly recall an explanation I read (I think it was by Gerd Isenberg) in the sense of that there actually ARE speed issues with large hash tables, related to the way how memory is handled by the OS. I am no programmer and I forgot the details of those explanations, but can you acknowledge that there is a speed impact - even if it's a small one - of large sizes?

It would make sense to me, considering for example that parts of a hash table may physically be on different RAM chips even. Also, many users clearly have the impression that they get better blitz results with small hash sizes like 64 or 128 MB or the like, while in theory it shouldn't harm to set 1 GB always.