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Subject: Re: Looking for help with computer problem.

Author: m.d.hurd

Date: 09:36:47 11/29/02

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On November 29, 2002 at 11:47:34, James T. Walker wrote:

>On November 29, 2002 at 03:05:19, m.d.hurd wrote:
>
>>On November 29, 2002 at 02:05:16, James T. Walker wrote:
>>
>>>On November 28, 2002 at 19:27:19, Jeremiah Penery wrote:
>>>
>>>>On November 28, 2002 at 17:11:08, James T. Walker wrote:
>>>>
>>>>>On November 28, 2002 at 16:54:25, mike schoonover wrote:
>>>>>
>>>>>>could it be that the master drive determines the access speed?
>>>>>>or,the system gives the master priority,hoging resources?
>>>>>>regards
>>>>>>mike
>>>>>
>>>>>Hello Mike,
>>>>>The only problem with that theory is the computer where the TB's are on the
>>>>>"Master" drive is the slow one.  The fastest one uses the 8G/5400rpm as drive C
>>>>>(Master) and the 40G/7200rpm as drive D (Slave).  The chess programs are on the
>>>>>"C" drive in both cases.
>>>>>Jim
>>>>
>>>>I would guess that the reason for the slowdown is because the virtual memory
>>>>(pagefile) is on the same drive as the tablebases.  So, when it caches
>>>>information, it's copying on the same disk, while also trying to access other
>>>>tablebases.  On the other machine, it copies to a different disk, which will be
>>>>much faster.
>>>>
>>>>Other things that can affect the access speed of tablebases are disk
>>>>fragmentation and the physical position of the tablebase files on the disk.  If
>>>>the files are heavily fragmented on one system, and are contiguous on the other,
>>>>the fragmented ones should be quite a bit slower.  Files near the beginning of
>>>>the disk have faster access times and faster transfer rates than files near the
>>>>end of the disk, as well.
>>>
>>>Thanks for trying to help.  I did de-frag the drive on the slow computer and it
>>>seemed to help some.  It now starts out at almost the same speed but slowly lags
>>>behind.  For instance, both computers will reach 14 ply in 15 seconds on one
>>>computer and 16 seconds on the other.  But when getting to say 16 ply at 2:15 on
>>>one computer it takes like 3:10 on the other.   Also as you might guess, the NPS
>>>on the computers gets further apart with time.
>>>Jim
>>
>>Hello Jim
>>
>>One thing worth checking is the EGTB cache size, which is set in Options. Mine
>>was set at 1 mb. It might be worth experimenting with different sizes to see
>>what difference each size increase makes. The help file says to use a value of 1
>>to 8 mbs. However I seem to recall someone mentioned 16 mb was a good size to
>>use. I suppose the bigger the cache, up to the optimum figure, the less disk
>>access.
>>
>>Regards
>>
>>Mike.
>
>Hello Mike,
>I'm using 16M I think.  Anyway it's the same for both computers.  I have gone
>through all Bios settings, all ".ini" files and everything I can think of to
>make sure the two computers are set up the same.  The only difference is the
>video cards plus the hard drives are backwards from each other.  It's a lot of
>work but I'm thinking of swapping the drives around in the slow machine to see
>if it helps.  I don't think the difference is critical since it only shows up in
>late endgames when the tablebases are being hit hard.
>Jim

I would imagine that the optimum EGTB cache would be different for each hard
drive. Some are faster at reading than others, some have a faster access time.

So setting both machines at 16 mb might not be optimum.


Regards

Mike



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