Very slow performance transferring files

[NRGetic]

Here's a toughie to crack
2 hard drives, both sata, 120 GB Seagate and 250 GB Maxtor

hooked up to a Asus P4P800SE board with p4 2.53 ghz cpu and 1024 mb of DDR333 ram Windows XP Pro SP2

now.... on a fresh windows install when i copy a file from one drive to the other it goes fast (700 meg file in under 30 seconds)... then I install all my basic software (office, winamp, visual studio, nod32, device drivers for manufacturers website) and following that eventually my performance drops through the floor... it takes like 7 minutes to copy the above mentioned 700 meg file and while at it the CPU usage is high. Process explorer (sysinternals) says that most of that cpu power is taken up by hardware interrupts and I cant do much else when its copying... If i boot with WinPE those files transfer good again... 30 seconds for 700 megs.

SO this is a software problem and what i've done already is
1. disabled my startups
2. double checked that my drives are DMA enabled
3. switched back to standard IDE drivers for the controller (made no difference so i reinstalled the Intel chipset drivers again)
4. defragged the drive

and i'm out of ideas on what else I could try... if anyone has any ideas i'd be greatful... there is no viri/spyware on this machine... its been scanned left right and center

 

[NRGetic]

its solved

the SATA 1 cables are sorta "loose" and once in a while they make the hard drive restart... doesnt happen often but maybe once a a month... anyway seems windows downgrades the DMA status of the IDE driver every time such an event happens eventually turning the DMA into PIO mode.... this explains why I was getting such high cpu usage during transfers and such slow speeds. The fix for it was to remove everything under "IDE/ATA devices" in device manager and rebooting... All is well now... I can copy gigs and gigs worth of stuff with less than 5% cpu activity and at MUCH greater speeds. my boot time seems to have been cut down about 2/3 so I'm happy... Hope someone can use this to fix their own as Ive seen this problem all over the place (i'm a techie)