Odd Raid 0 Disk Speed Results

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Seraphic

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I have six hard drives here.
Three WD6401AALS 640GB (I'll call raid Array1)
Three WD6400AAKS 640GB (I'll call raid Array2)

Now each of the three sets of drives are in their own raid 0 array (about 1.7TB each).
I ran some disk read/write tests and found something that seems odd.

Array1 had:
Data Read Speed: 319.3 MB/s
Data Write Speed: 318.3 MB/s

Array2 had:
Data Read Speed: 306.3 MB/s
Data Write Speed: 296.8 MB/s

So the result is that Array1 is faster then Array2.
However, Array1 is the OS (Vista X64) install drive.
So shouldn't Array1 be slower or are the "black" drives that much more faster then blue?

Also, does it matter what sata plugs are used in the motherboard?
For example, if motherboard has six sata ports, will the drives in 1-3 always have higher allocated bandwidth then drive 4-6?
I think I recall setting Array1 in ports 1-3 and Array2 in ports 4-6.
 
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The Blacks are faster than the Blues, apparently just a little. The numbers look very reasonable.

Dustin
 
Yes, but I always thought whatever drives had the OS installed to it would be have a good deal slower read/write.
 
Whether the OS drives' benchmark results are affected depends on the level of activity on that drive while benchmarks are being done. If you're not running any background tasks that place a load on the OS drive, then the results shouldn't be any different than for a non -OS drive. It's when disk intensive tasks such at BitTorrent or Windows Indexing are going at the same time as the benchmark that you'll see slower results.

Dustin
 
On rotating media, read and write speeds differ depending on the location that the data resides on the disk. Early partitions and data are faster than later ones.

So, depending on how full your volumes are, how they're partitioned, and which software you're using for your throughput tests, the results can vary by quite a bit. Between that and the fact that you're using two different kinds of drives, your results don't seem surprising at all.
 
im not too impressed with my 3 640AALS in Raid 0 over 2.. dunno if its the onboard raid controller or what. but i only seem to be averaging like 210MB/s ect vs 185/190 with only 2.

i have an Asus P5Qpro and the hard drives are on SATA ports 2 3 4, port 1 has a single 640AALS which has the OS on it. i wanted to put all 4 into a single array but i dont have any where to hold around 500GB of data right now to be able to whipe all 4 at the same time.
 
I think it might be your controller. Those speeds seem kind of slow vs my speeds and I'm using on-board controller myself.
Would really like to see what speeds I get with five or all six drives in a raid 0, but...
1. Not sure if you can mix WD6401AALS and WD6400AAKS drives.
2. Damn 2TB limit!!

Also, like I asked before, does it matter what sata plugs are used in the motherboard?
For example, if motherboard has six sata ports, will the drives in 1-3 always have higher allocated bandwidth then drive 4-6?
I think I recall setting Array1 in ports 1-3 and Array2 in ports 4-6.
 
Seraphic said:
I think it might be your controller. Those speeds seem kind of slow vs my speeds and I'm using on-board controller myself.
Would really like to see what speeds I get with five or all six drives in a raid 0, but...
1. Not sure if you can mix WD6401AALS and WD6400AAKS drives.
2. Damn 2TB limit!!

Also, like I asked before, does it matter what sata plugs are used in the motherboard?
For example, if motherboard has six sata ports, will the drives in 1-3 always have higher allocated bandwidth then drive 4-6?
I think I recall setting Array1 in ports 1-3 and Array2 in ports 4-6.
Click to expand...

what program did you use to test the speed of the drives? both HDTach and HD tune give me similer resaults (im in Windows 7) only my Black Magic Intensity Pro software thats used to test hard drive perf. for HighDef captures shows the drives at 320MB/s but that seems more like a burst speed when both hd-Tune/Tach show the 3 drives topping out at 220 average and tach shows a 360-80 burst
 
Yeah, I used the Black Magic Intensity speed test for my results.
Thinking it would be the same as any other speed tester.
What program to you suggest?
 
Seraphic said:
What program to you suggest?
Click to expand...

use HD Tune and/or HD Tach both should be free to dl

i just ran the black magic test to see how my 3 are, and it shows them at 329 read 319 read. but for some reason i doubt that is really accurate
 
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