Okay, heres the skinny

AS 11 running on a dedicated HP ML370 G2 with 4gb RAM
3 tape drives - 1 AIT, 1 DAT72, 1 Ultrium

Several months ago (GRRRR...I can't pinponit exactly when this started happening, but I think it was before our upgrade to 6.5 from 5.1sp6) our backup to AIT took less than 8 hours.

Now, to the same drive, its taking 30 hours. The throughput in kb/min is 17,100, which seems INCREDIBLY slow.

On the server that is currently backing up, SMDR is the # 1 busy thread...the primary CPU is pegged at 70% (Hyperthreading is off)

Anything that jumps out at you for things to try?