Write speed RAID 0 to slow

[Rowi 0]

Can anybody help me in getting my raid 0 working well?

I use a KT3 ultra aru mobo with onboard raid controller (Win Xp Promise MBFast Trak 133 Lite) PDC20276, AMD Athlon XP2100+, 1 x HDD Maxtor 40GB 6E040L0 (Win XP and applications), 2 x HDD Maxtor 40GB 6L040J2 in raid0 stripe mode.

I had several problems installing Wip XP (probably caused by the raid drivers), but in the end I managed to get it working.

Installing raid wasn't such a problem (I thought) untill I performed a disk benchmark (ATTO) and found out that in particular the write speed of the raid was very disapointing. Write speed is 12MB/sec, read speed is 52MB/sec, while the stand alone disk does 43MB/sec for write speed and 42MB/sec for read speed.

I checked and double checked every possible connection and setting, but I can't find where it goes wrong or what setting I've missed.

Raid drivers are: 2.0.1000.34 Raid setting: Stripe A/V editing

Is there anyone who can give me hints or tips to increase the write speed?

Thanks in advance.

Ron.

[Tomay 0]

When setting up a raid0 you can set the stripe size. I think default is 16kb (not sure). Maybe this setting will have an influence.

 

BTW when working with large files stripe size of 512 or 1024KB is recommended.

[jmmijo 1]

I think the default block size is 64K for many RAID controllers, both SCSI and ATA/SATA.

 

However I'm not sure this will effect the write speed so much as the read speed

[Rowi 0]

Stripe size has been set to the maximum (A/V editing) already, so that's not the problem.

[sapiens74 0]

IS that a Via Chipset?

 

If so Via chipsets are known to have trouble with Raid Thoroughput

[Rowi 0]

It's a VIA chipset indeed.

I've had such a lot of trublle with this RAID that I'm considering to forget all about the RAID and buy a 120MB HD instead.

[Newumbrella 0]

You should test the HDs with HDTach 2.7 for the burst speed (or the interface performance). The normal values should be 75 or higher. If you get a lower figure, it's probably caused by PCI latency timer set too low.

 

I'm using MSI KT3-Ultra ARU as well (w/ latest BIOS, 5.7), and i've found out that the "PCI latency timer" option in BIOS is actually non-functional. Because I've used WPCREDIT to check the actual value, and whatever you set in BIOS, the actual value is always at 32 (which is way too low).

 

So try to use WPCREDIT (with KT333 PCR file) to change the value, and use WPCRSET to apply the setting every time windows started.

 

I have all the files you need so if you need them by any chance i'll post the link.

 

P.S. I think the reason that VIA's chipset have bad add on PCI IDE adapter performance is because often the PCI latency timer is set at the inappropriate value, and these adapters need more piority to function at the optimum level.

[gsc4 0]

I have a different motherboard (GA 8INXP) with the same controller and I had the same problem.

 

My solution was to enable the SATA RAID controller in the BIOS (in addition to the ATA RAID controller that was writing slowly). I guess, the two controllers must share some common component.