RAID 0 Speed question

[domburi]

I have a question about my setup and RAID 0 speeds and hard drive speeds in general. I don't seem to be getting what I should out of my setup.

*all hard drives in this post are Western Digital 7200k rpm Special Edition Drives (8mb cache)*

I recently setup a computer with an Adaptec 1200a RAID card and configured a RAID 0 array. Installed Windows XP Pro and benchmarked it with SiSoft.

System Specs:
Intel D865PERL MB
Pentium 4 2.8 800mhz bus 1mb cache
2 x 512mb Crucial PC-3200 Dual Channel
2 x 120GB WD Special Edition HD (8mb cache)
Adaptec 1200a ATA RAID card / RAID0

It averaged 65mbs. Wow, pretty good I thought!

I decided to put a RAID system in my home computer.... I went for an Adaptec 2400a ATA RAID card (has 32mb cache) and setup RAID 0 - two of the same HDs. My System Specs:
Epox 8RDA+ MB
Athlon XP 2800+
2 x 256mb GEIL PC-3200 Dual Channel
2 x 120GB WD Special Edition HS (8mb cache)
Adaptec 2400a ATA RAID Card / RAID0

I ran the same SiSoft benchmark and got a result of 41mbs not too good.

I also have a Western Digital 180GB Special Edition and a Western Digital 200GB Special Edition in my system. Curious, I benchmarked those:

(Both are master drives on their own channels.)

WD 180GB (IDE0): 29mbs
WD 200GB (IDE1): 43mbs

I am totally stumped. I don't know where to go from here. I was expecting at least 60mbs with the RAID and now I'm finding out that my 200GB drive is actually the fastest. I also have NO idea why the difference between the WD180 and the WD200.

Futhermore, i copied the system partition from the RAID to the 180GB drive and ran the benchmarks again thinking maybe the drive that windows was on was doing something to the results. I got the same results booting from a different drive.

The only thing I think of is to try an Adaptec 1200a card. But why would a lesser card give better results? the 2400a is like $250 more!

Any ideas!? THANKS for reading such a long post!

 

[cdogg]

The Adaptec card is not likely the problem. The main differences between the two machines is chipset, bus speed, and probably BIOS. I would make sure you have all updates installed on the EPOX PC including BIOS revisions and chipset driver updates in Windows. There must be some kind of flaw with the way the controller is interacting with the chipset or BIOS instruction sets.


~cdogg
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[jurgen36]

We had similar problems with Adaptec raid cards. We now use the Sil 3112 raid controllers in raid 0 mode. Sustained data transfer rates are between 88 and 91 MBytes a second. Burst rates are 128 Mb. Your limitation could be that your card works through the PCI bus which limits your bandwith. Regards

Jurgen