Slow SCSI Speeds?

Discussion in 'General Hardware' started by g3w, Mar 21, 2002.

  1. g3w

    g3w Guest

    Hey there, hope alls well.

    Have just ran that PC-Pitstop checker over my system (http://www.pcpitstop.com) and have been dismayed by the woeful performance my HDD are giving me.
    (i'll not tell you my score for fear of laughter hehe)

    I have one 9.1Gb Quantum Atlas III SCSI drive, partitioned into 2 drives, C:\ system drive, about 3 Gb, and D:\ data & installs, about 5.6Gb.

    The SCSI HDD is hanging off an Adaptec 2940AU SCSI card.

    The results of the PCPitstop tests are:

    C:\ Cached speed = 33Mb/Sec (50%)
    D:\ Cached speed = 114.37Mb/Sec (173%)

    C:\ Uncached speed = 1.19Mb/Sec (48%)
    D:\ Uncached speed = 1.77Mb/Sec (72%)

    I do not understand why, if they are one and the same physical disk, there is so much performance difference, especially in cached speed.

    I have relocated my page file onto D:\.. would this make a difference?

    Both my memory and processor speeds both rated 108%, ie slightly better then Pitstops library of similar systems, and I thought cached speed relies mainly on the speed of the processor and memory as opposed to uncached which relies on the speed of the disk?

    Can anyone give me any ideas as to maybe what to look for to get a bit better performance out of my SCSI set up?

    Thanks!
    G3W
     
  2. Qumahlin

    Qumahlin Moderator

    Messages:
    2,006
    DO NOT move your page file to a partition that windows is NOT on

    for example..if windows is on C put the swap file on C or else degraded performance occurs because the drive head has to jump around to read and write data from one part to another

    the only time you should put a partition anywhere else is if you have a separate PHYSICAL drive since the controller can process read and write requests concurrently
     
  3. g3w

    g3w Guest

    OK well I have now removed the page file altogether (I think my 320Mb should be enough to cope with the few tasks I use this PC for)

    I'll go and run PC-Pitshop again and see what stats i get this time.

    ta!
    G3W
     
  4. g3w

    g3w Guest

    Yah !

    OK removing that damn paging file seems to have done the trick, for caching anyways.

    With NO paging file installed I've run the tests again and the results this time are

    C:\ Cached speed = 78.1Mb/sec(118%)
    D:\ Cached speed = 87.4Mb/sec(132%)

    C:\ Uncached = 1.17Mb/sec(48%)
    D:\ Uncached = 1.65Mb/sec(67%)

    I'm quite happy with those caching scores - a lot more what it should be.

    Can you think of any reason why C:\ would be a bit slower? Simply because maybe the system files and Browser caches are on it and is probly less defraged?

    ahh good it's over the 200 mark now lol.

    later!
    G3W
     
  5. Qumahlin

    Qumahlin Moderator

    Messages:
    2,006
    it would be slower due to it's location on the physical disk, location on disk effects speed :)

    you might want to keep a page file...just make sure it is on the windows part :)