Copying Speed Slows Down as Copying Progresses

[Soopafresh]

I'll start a copy - 3GB worth of 30MB files from one SATA drive to another identical SATA drive inside the same PC.

Performance starts out at 30MB/sec transfer rate, then as the copying progresses it drops down to 1.4MB/sec

CPU usage hovers at only 3%

Machine has 8GB RAM (only 814 in use). No other processes running. No antivirus protection installed.

Then I'll run the copy again and it flies on through at 100MB/sec

?

EDIT: I'm thinking it has to do with NTFS file compression, which I've enabled on one of the drives.

[johns0]

Sounds like a driver problem for your sata-ide drivers,are they nvidia drivers installed?My sata to sata copies at 60mbytes with no slowdown.

[Soopafresh]

thx, yes it's an nvidia mobo.

[johns0]

Best to install the microsoft drivers for your ide controller,nvidia ide drivers are known to cause those problems.