Posted by: John Barshinger | August 18, 2009

Intel X25-M SSD RAID 0 Performance/How to zero out/reset to factory performance?

This past weekend I bought a second 80GB X25-M from NewEgg.com because they were on sale for a good price. (note: I’m talking about Gen 1 X25-M’s in this article). I liked having an SSD running under Windows 7 for my software dev box so much that I decided it can only get better if I get another and stripe two of them in a RAID-0 set. I assumed this would help me in two ways: first this would give me approximately 150GB of disk space instead of 75GB; and second, I expected read and write performance to scale to almost double what I get in a single drive. Now read performance is excellent on a single drive, Intel claims up to 250MB/s. However, write performance, although good, could be better. Intel claims write performance of up to 70MB/s. So, I was expecting to throw these 2 SSDs in a RAID-0 set served up by the Intel ICH10R on my ASUS P5Q-E motherboard and get around 400MB/s read and 140MB/s writes. Here’s what I actually found:

test MIN MAX AVG Acc Time Burst CPU
SSD1-R 178.6 221.3 209.1 .1 98.8 2.8
SSD2-R 110.9 221.7 200.6 .1 101.5 2.7
SSD1-W .1 78.4 66.8 .1 98.9 1.8
SSD2-W 36.9 77.8 71.6 .1 101.2 1
STRIPE-R 145.3 336.7 258.2 .1 146.9 6.6
summed-R 289.5 443.0 409.7 .1 200.3 5.5
STRIPE-W .2 135.8 87.1 .1 95.4 2.2
summed-W 37.0 156.2 138.4 .1 200.4 2.8
STRIPE-W+ .7 152.5 116.9 .1 837.7 3.9

 

SSD1-R is the read results from HDTune for reading on my first Intel X25-M. SSD2-R is the read results from HDTune for my second Intel X25-M (both are using AHCI and treated as single drives in the BIOS). Similarly, SSD1-W and SSD2-W are the HDTune results for writing.

summed-R and summed-W are simply the sum of the results I got from both drives in individual Read and Write tests. These are the numbers that ideally I would like to see in the striped set.

STRIPE-R shows the actual numbers I got for reading the striped set of SSDs. STRIPE-W shows the actual numbers I got for writing the striped set of SSDs. STRIPE-W+ is the same as STRIPE-W except that I turned on write-caching for the RAID volume via Intel Matrix Storage Manager.

As you can see, the striped set got me nowhere near my expectations, every metric for STRIPE-R and STRIPE-W was much less than ideal amounts calculated by summing the individual drives metrics.

One thing that really bugged me was the very low MIN write times for the individual SSD test. Take a look at these pictures and you can see ridiculous spikes in the performance graphs from HDTune.

SSD1-W (above)

SSD2-W (above)

Those are not what I call pretty graphs. The thing to remember with SSDs (in layman terms), is that once every page on the disk has been written to, in order to write to that page again, the SSD must first erase (clear out all the electrons) in every bit on the page prior to writing the actual data. This could explain what we’re seeing above.

Now what about reading? Let’s take a look at those graphs:

SSD1-R (above)

SSD2-R (above)

The read graphs above are not too bad but still not very smooth. I have no explanation for this result…

Well, the next thing I decided to do was try to figure out how to restore these SSD’s to factory performance by clearing all the pages on each SSD. After searching for some time, I found this page: http://www.pcper.com/article.php?aid=669&type=expert detailing how to zero out the SSD’s. This page: http://www.pcper.com/article.php?aid=669&type=expert&pid=6 also provides a download link to the correct version of HDDErase that will work with these Intel SSDs.

So I went to work on zeroing out these SSD’s… Afterwards, I re-ran the HDTune tests and here are the resultant graphs:

SSD1-R (above)

SSD1-R (above)

Now those are some nice smooth read graphs!

SSD1-W (above)

SSD2-W (above)

Still a little spikey on writes but not bad at all! I’ll take it!

STRIPE-R+(above) write caching turned on in Intel Matrix Storage Manager for this striped volume

nice and smooth, average 479.3MB/s reads, WOW!

STRIPE-W+(above) write caching turned on in Intel Matrix Storage Manager for this striped volume

not bad at all! average 148MB/s for writes, now we’re talking!

———————————–

Now what does this all mean??? For peak write AND read performance, we’re going to have to image our hard drive, secure erase each SSD, and then put the image back on our stripe-set. This really sux! The good news is that newer SSDs including Gen 2 of Intel X25-Ms will support TRIM which will automatically zero out the pages on the SSD that are no longer in use at more opportune times than when you want to write to that page. Windows 7 has TRIM built in, so you should be all set after some number of firmware and windows updates have been completed down the road when TRIM will be working in all its glory… Until then, image, secure erase, un-image for peak performance. Oh and don’t forget, each time you write or zero out a page on your SSD, that is one less time you will be able to write to it before it fails. They don’t call this the bleeding edge for nuthin, folks!

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Responses

  1. I have two intel x25-m 80gb ssd, one is first gen, the other is second gen. Could I still put these two drives in raid. I did update intel firmware on both drive.

  2. yes, but if you RAID SSDs, TRIM will not work. If I was in your situation, I would use the Gen 2 as my boot disk so that TRIM will work, assuming you are using Windows 7 (Windows 7 is currently the only OS that supports TRIM at this time). You never need to zero out the Gen 2 SSD because it supports TRIM as long as it is running Windows 7. TRIM keeps your Gen 2 running optimally all the time, no zeroing out is ever needed.). Then use the Gen 1 SSD as your data drive. This way you only need to zero out your data drive to get max performance from it and it\’s a lot easier to backup/restore a data drive than a system drive.


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