W520 Slow READ from Ultrabay??

[plympton]

I'm making a new thread for this, since it's so bizarre for me.

I have a W520 Q2720, 12 GB ram, and 2.6 BIOS. It runs great, except 1 weird problem - the Ultrabay drive READS at 7 MB / sec. I can write to it at 100MB/sec from a USB 3.0 drive, but READING is painfully slow.

W.T.H?

So, W520 (RAID enabled BIOS, RAID disabled), Q2720, 12GB Ram, Vertex 2 90 in the main drive, 320 7200rpm in ultrabay (OEM RAID drive, RAID disabled & reformatted), 1 TB on USB 3.0. All drivers up to date, Windows 7 64 Pro.

Copy functions:
3GB from USB -> Ultrabay: 100MB/sec
3GB from Ultrabay -> USB: 7MB/sec
3GB from USB -> USB (copy to itself): 45MB/sec
3GB from Ultrabay -> Ultrabay (copy to itself): 5MB/sec

EDIT: HD Tune bears this out - SSD: 130+MB/sec, USB 3.0: 100+ MB/sec, Ultrabay: 7MB/sec

Anyone know how to even debug this? It's driving me crazy!

Thanks!
-Dan

[plympton]

I found the answer - it appears that since I didn't tell the Intel controller that the drive was no longer a RAID drive (I have an SSD and the HD for storage), it thought I still had a degraded RAID mirror, and was probably waiting to rebuild it.

Strange. The drive was even formatted in Windows and everything.

Anyway, after re-enabling RAID (instead of AHCI) in the BIOS, and using the Intel RAID BIOS functions to make the drive non-RAID (saying it would erase it, but it didn't), it now reads at full speed.

Anyway, one for the archives....

-Dan