Dual Xeon + HW RAID question

Hi,

I have this machine with a 10 million records:
* Dual Xeon 2.0 (HyperThreading enabled), 3 7200 SCSI , Adaptec 2110S,
RAID 5 - 32k chunk size, 1 GB Ram DDR 266 ECC, RH 8.0 - 2.4.18

The database is mirrored with contrib/dbmirror in a P4 1 Gb Ram + IDE

If a disk failure occurs, I can use the server in the mirror.

I will format the main server in this weekend and I have seen in the list
some people that recomends a Software RAID instead HW.

I think too remove the RAID 5 and turn a RAID 1 for data in 2 HDs.
SO, WAL and swap in the thrid HD.

My questions:

1) I will see best disk performance changing the disk layout like above
2) HyperThreading really improve a procces basead program, like postgres

Thank´s for all

Alexandre