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Subject: Re: Tip: how to reduce hard drive churning with tablebases

Author: Slater Wold

Date: 21:11:54 03/08/04

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On March 09, 2004 at 00:07:10, William Penn wrote:

>On March 08, 2004 at 23:52:53, Slater Wold wrote:
>
>>On March 08, 2004 at 23:49:58, William Penn wrote:
>>
>>>Pretty simple. Reduce hash size. That's the only thing I've found to have a
>>>significant effect when tablebase access starts to churn the hard drive
>>>constantly. Engine speed (kN/s) falls dramatically at that point, perhaps to 10%
>>>or less of normal speed, and never recovers. However using smaller hash size
>>>appears to fix this problem.
>>>
>>>For example my computer has 1G RAM installed. I can run Shredder 8 with 768MB
>>>hash normally, although I often use 512MB which the op system prefers a bit
>>>more. Now one would think that 512MB hash would be OK in any situation with 1G
>>>RAM, but not so. It's too much hash when tablebase access starts to crank up
>>>heavy in endgame situations. At that point, reducing hash size to 256MB usually
>>>fixes this problem, restoring engine speed to a reasonable kN/s. I haven't yet
>>>found it necessary to goto 128MB hash.
>>>
>>>[Windows XP Home, Athlon XP 2400+/2.0GHz, 1G RAM]
>>>WP
>>
>>Your HD is 'churning' because it is access a database on your hard drive.
>>
>>Your nps drop because the engine has to wait on info from your hard drives.
>>
>>The 'churning' is not a problem.  Your HDs are.
>>
>>Go SCSI.  Or at the very least, 10k SATA.
>
>Churning IS a persistent problem! How can you say it is not the problem? Of
>course it is the problem! All you have to do is sit here and watch the hard
>drive activity light, and listen to the drive churning constantly. Access never
>stops.

That's what TBs do!  That's not the problem!

>My hard drives are NOT a problem! There is nothing wrong with them nor my
>computer. I have two 7200rpm Maxtor drives, 120G and 80G. And the windows
>pagefile is also optimized on its own dedicated partition.

The average seek time on a Maxtor DiamondMax Plus 9 is about 9.3ms.

The average seek time on a Seagate U320 15k RPM SCSI drive is about 3.6ms.

Effectively 3x faster.

>Sorry but I know nothing about SCSI. If that would require buying different hard
>drives, then it's not an option for me.
>WP

You would have very little drop in nps with the SCSI drive.  But the 'churning'
would persist.  The 'churning' is part of HD access.



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