PE 840 very slow

[Richard DeSimine]

(this is my 1st post to this forum)

I got new PowerEdge 840 loaded with RedHat Enterprise 5.1, 4GB ram and a
2.4ghz QuadCore processor. 

>uname -a
Linux <hostname> 2.6.18-53.1.4.el5 #1 SMP Wed Nov 14 10:37:27 EST 2007
x86_64 x86_64 x86_64 GNU/Linux

It has a SAS5/IR (SAS) card and 2 250GB ATA drives configured as RAID 1.

Disk I/O is slow. Very SLOW. Comparing it to the PowerEdge 700 which I
am upgrading, which is a single CPU single drive 2.3ghz Pentium, the
disk writes take about 8x longer on the new 840. Furthermore, when any
process is performing I/O, no other process can get access to the disk,
and all process effectively are hung.

Is anyone else experiencing this problem?

Thanks,
Rich