To use Intel® Application Accelerator or not?

[Deadtrees]

My system:
P4P800
WD 120mb 8mb cache.


I'm not sure if this is something I should install or not. It sounds alright but I've read somewhere that it doesn't really make any difference and it may actually decrease the speed of HDD.
Should I or Should I not?

 

[MDE]

I don't even know what it does, but I installed it. Didn't seem to do anything that I noticed.

 

[KDKPSJ]

IAA doesn't support Intel 865 and above chipsets, unless you use SATA-RAID of ICH5-R. You can not even install it if you don't use RAID. (But if you use RAID by ICH5-R, it's strongly suggested to use IAA RAID. It's known to give pretty much performance boost)