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View Full Version : 20% cpu usage normal for Raid 0..........


Sipster
08-17-2008, 02:42 AM
that seems high to me......what do you think? Using onboard Raid and yes I do have the latest drivers for mobo, raid, OS,etc....
Ran test multiple times......same results!

Raid 0 scores:

min: 71.4
max: 125.2
avg: 104.5
access time: 15.0
burst rate: 165.1
cpu usage: 20.0%

Single drive scores:

min: 35.3
max: 72.6
avg: 58.3
access time: 15.0
burst rate: 137.5
cpu usage: 3.1%

AVT
08-17-2008, 02:53 AM
Are you using onboard RAID?

edit: I can't read. *smacks head against the wall*

bigdogchris
08-17-2008, 05:28 AM
Yah, it's normal. I just got away from my raid array due to instability, but I was getting about 14-22% cpu usage on benchmarks in raid-0.

You can turn on the additional Disk performance setting under the drive, in device manager. That reduces your CPU usage but decreases transfer rates as well.

Ockie
08-17-2008, 09:36 AM
Thats what a lot of people don't get about consumer raid 0 concepts. Not only is the raid controller in your board not as performance driven like a real controller, but you get taxed on your cpu performance.

The Hunter
08-17-2008, 10:24 AM
While I fully understand why some CPU overhead is expected, I don't really get why it's so much. There's no parity calculations with Raid0, it should be a fairly simple operation.

Is it possible that it's skewed due to the test accessing the whole disk, vs. a day-to-day operation of much shorter periods of access?

bigdogchris
08-17-2008, 04:42 PM
While I fully understand why some CPU overhead is expected, I don't really get why it's so much. There's no parity calculations with Raid0, it should be a fairly simple operation.

Is it possible that it's skewed due to the test accessing the whole disk, vs. a day-to-day operation of much shorter periods of access?Because it's sequential reading of large files for throughput benchmarking. That's why it's called a synthetic benchmark. You're not going to have 20% cpu utilization at all times. When I went from 1 drive to raid 0, I did not notice any more cpu utilization in task manager than I did before.

My opinion on raid has changed though after using it. I will never use striped raid again for the primary partition. My OS will always be on 1 disk or be mirrored. I would consider using striping if I was in a situation where large files needed to be pulled off and written constantly but for normal computing and gaming, never again.

H911
08-18-2008, 03:24 AM
Pretty normal for onboard raid

Sipster
08-22-2008, 02:06 AM
Just an update......

So I installed my 2 new 320 GB 7200.11's in Raid 0 and Wow.....nice jump in performance.....and cpu usage went way down.

Old 7200.10 Raid

min: 71.4
max: 125.2
avg: 104.5
access time: 15.0
burst rate: 165.1
cpu usage: 20.0%

New drives

min: 119.0
max: 224.0
avg: 177.9
access time: 19.7
burst rate: 339.7
cpu usage: 8.0%