Have a look at these pages: http://www.bofh-hunter.com/2008/06/13/3ware-performance-in-centos/ https://bugzilla.redhat.com/show_bug.cgi?id=444759 I'm comparing the default 5.1 64bit kernel with the patched one posted in the bug report (kernel-2.6.18-53.1.21.el5.bz321111.x86_64) and I don't quite see any significant difference in write performance for this command: dd if=/dev/zero of=/logs/test bs=100M count=1000 (100GB of data, written in 100MB blocks) It's a Supermicro server, the motherboard is (according to the stuff painted on the mobo itself) Super X7DBI+, Intel Xeon L5420 with 8 cores total, 3ware 9650SE using the driver from the manufacturer's site. I tested 2 disks in a mirror RAID volume. Results: kernel time speed ====== ==== ===== patched 75min 23M/s original 51min 34M/s patched 48min 36M/s original 61min 28M/s -- Florin Andrei http://florin.myip.org/