x64 SATA HDD to HDD file copy slowdown

New install of Vista Ultimate x64. Drive C is a new drive which works
well. Drive D is an older SATA 3.0 drive - both WD. When copying from
drive D to drive C with large files the transfer starts out well enough
at 55Mb/sec and slows down once around 2.5 GB are transferred. It slows
down almost at once to a stop, and then continues at 100kb/sec. What in
the world is causing the change? ICH9R is the chip on the motherboard
(ASUS P5K Pro). I had the SATA set for IDE at first, then updated to
ACHI using Microsoft's regedit update to enable ACHI after Vista was
installed. This slowdown happens in both cases. Drive C to an external
HD via firewire does not exibit this slowdown, but drive D to the same
external HD does.

Any ideas for me to look at and try?


--
Skyham

Have you upgraded to SP1? There are changes introduced into SP1 that
address situations like this.


"Skyham" <guest@unknown-email.com> wrote in message
news:332f47d216067db8278c1d57dd3fa92e@nntp-gateway.com...
>
> New install of Vista Ultimate x64. Drive C is a new drive which works
> well. Drive D is an older SATA 3.0 drive - both WD. When copying from
> drive D to drive C with large files the transfer starts out well enough
> at 55Mb/sec and slows down once around 2.5 GB are transferred. It slows
> down almost at once to a stop, and then continues at 100kb/sec. What in
> the world is causing the change? ICH9R is the chip on the motherboard
> (ASUS P5K Pro). I had the SATA set for IDE at first, then updated to
> ACHI using Microsoft's regedit update to enable ACHI after Vista was
> installed. This slowdown happens in both cases. Drive C to an external
> HD via firewire does not exibit this slowdown, but drive D to the same
> external HD does.
>
> Any ideas for me to look at and try?
>
>
> --
> Skyham

One of the first things I did was to install Vista64 and load SP1 prior
to connecting this second drive. I think it may be a drive fault. I
pulled this drive from another machine, and I had to jumper it to run at
1.5 MB/s (SATA1) in order for it to work in the old box, and I had
thought it was a motherboard issue there. If I try to re-jumper the
drive to SATA2 3 MB/s Vista sees it, but not as an available drive. In
the diskmngr it appears, but won't initialize it complaining of an
unspecified error. If I jumper it to turn spread spectrum on it doesn't
work, only as it was originally set at the slower rate. I have another
drive on order which should be delivered tomorrow and my question will
be answered one way or another.
Thanks for your thoughts.


--
Skyham