SATA RAID: 3ware vs. Promise

[vladimir konrad]

i know this is about different promise controller to mine (and also
under different operating system) but here is my experience.

i am using promise ex8350 under debian linux (sarge) and the 2.6.20.1
kernel (one >2TB raid 6 array).

one problem i am experiencing that it cannot sustain write performance.
if i do:

cat /dev/zero > /directory-on-the-raid-conntroller/out.tmp

the write speed is ok to begin with but after about 20 seconds it drops
to about 1MB/s. if i do the same on different machine (with software
raid 5), it will keep going at around 20MB/s (this one is a slow box).

the last message i sent to promise support on 7 march 2007 (with
more information, like bios, firmware versions and such) is still
unanswered (i hate that).

it could be driver/firmware/bios settings or incompatibility but as
promise did not respond to the last query, i cannot tell.

personally, given a chance i would try something else then promised
stuff next time...

vlad