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Force GT 90 GB raid 0 Slow write speeds...


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Clean install of win7 64 bit upon doing some tweaks read speeds are nice @ 925MBs. Write speeds are CRAP @ 255MBs. Any idea's as to why or how to fix? all gear was bought 2 weeks ago. Only thing I didn't do was check on what firmware the drives are running.
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Uploaded atto benchmak looks great but why do other's say differently? I would expect to see similar write performance with other programs.

 

 

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CrystalDiskMark 3.0.1 x64 © 2007-2010 hiyohiyo

Crystal Dew World : http://crystalmark.info/

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* MB/s = 1,000,000 byte/s [sATA/300 = 300,000,000 byte/s]

 

Sequential Read : 974.362 MB/s

Sequential Write : 267.323 MB/s

Random Read 512KB : 792.203 MB/s

Random Write 512KB : 257.139 MB/s

Random Read 4KB (QD=1) : 37.561 MB/s [ 9170.3 IOPS]

Random Write 4KB (QD=1) : 248.675 MB/s [ 60711.7 IOPS]

Random Read 4KB (QD=32) : 237.685 MB/s [ 58028.5 IOPS]

Random Write 4KB (QD=32) : 248.222 MB/s [ 60601.0 IOPS]

 

Test : 1000 MB [C: 37.2% (59.2/159.2 GB)] (x5)

Date : 2012/03/07 19:43:00

OS : Windows 7 Ultimate Edition SP1 [6.1 Build 7601] (x64)

 

 

 

AS SSD Benchmark 1.6.4237.30508

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Name: Intel Raid 0 Volume SCSI Disk Device

Firmware: 1.0.

Controller: iaStorA

Offset: 103424 K - OK

Size: 159.30 GB

Date: 3/7/2012 7:56:41 PM

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Sequential:

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Read: 960.62 MB/s

Write: 252.19 MB/s

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4K:

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Read: 27.15 MB/s

Write: 213.58 MB/s

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4K-64Threads:

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Read: 259.67 MB/s

Write: 204.17 MB/s

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Access Times:

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Read: 0.107 ms

Write: 0.037 ms

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Score:

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Read: 383

Write: 443

Total: 995

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645190956_attobench.jpg.12adb30f91676adeb29738bf92f82d2a.jpg

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That's simple, it's due to the SandForce (SF) controller in your SSD. Generally speaking, depending on the data, some is compressible (like a bunch of zeros or ones used for some testing) and some is not (a video file.) The SF controller has a special feature that compresses data when possible, so it actually writes less data to the SSD, so in that case it's writes are faster. It's a good feature that also increases the life of the NAND storage chips, which sustain wear from writing more than anything else. The compression -decompress process is very fast, so no performance penalty. ATTO uses all compressible data for it's tests, thus great write speed results for SF SSDs.

 

But give a SF SSD all non-compressible data (as used by AS SSD) and it's write performance becomes equal to or less than a non-SF controller SSD. Read speed is not affected by this. Other tests use a mix of compressible and non-compressible data, so the results vary.

 

The usual real world ratio of compressible to non-compressible data is about 2/3 compressible, 1/3 non-compressible. So in real world usage, the SF based SSDs perform great, but their performance will actually be between the ATTO results and the AS SSD results.

 

The only down side to the SF controller occurs if you fill your SSD to or close to it's capacity. It's performance tends to drop in that situation, as all SSDs do, but it tends to have a harder time recovering it's speed for some reason, after some of the space is freed up. Overall the SF controller works great, but nothing is perfect.

 

One question, do you have Write-back Cache enabled in the IRST software? Enabling that increases write speed quite a bit.

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Parsec,

 

thank you! Now it makes sense. I havn't been able to find anything remotly explaining this. Yes write-back cache is enabled. When it was disabled i was getting 170-180 mbs. I'm only at 37% capacity so there is plently of space on there.

 

So question should I use the compression feature in win 7 to save more space on the drive?

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