Dual SSD RAID0 Benchmark Results

It's nowhere near as fast as I had hoped

I'm running a Crucial M4 64gb + Samsung 830 64gb in RAID0

Any ideas why there's practically no improvement in performance?

 

If this is on your R4 there could be a couple reasons. i would blame it mostly on the fact they are 2 completely different drives. in order to use the RAID effectively you must use 2 identical drives. The other problem i ran into last time i tried to RAID 2 SSDs. the TRIM feature cannot be utilized. This means the drives can't delete the garbage files that slow the SSD down. think of it like Defragmenting a standard hard drive. If your TRIM feature is disabled the drives will be at least half the speed they should be. Especially if they had data on them before you reinstalled windows on them as a RAID.

 

As a reference, I use 2 x Samsung 830 in raid0, these are the scores i get without any tweaks.
It's on an m18x-r2 though, but should still be fine for reference.

Lemme think what could be wrong (something is definitely off with your speed). Have you checked the firmwares on the drives (and the drives themselves) to be identical?


edit: did you literally mean you raid0 your Crucial drive with your Samsung 830 drive?
If that's the case then we don't need to look why you have performance problems. THAT is the reason
You need 2 identical drives, preferably same size, but definitely same brand/model.

You risk running into a lot of potential problems with the setup you have used as raid0, both performance and even data loss and weird stuff going on in your OS you wont even be able to track back down to the SSD's.
I think you will even get better speed results while using the 2 SSD's as separate drives instead of raid0. If you want them to be 1 big drive you can always extend the first SSD with the second one in Windows to make it 1 large drive (no need to raid0 for that).

 

Yup, I've tried it with 2 different drives and as jiggymf says it's not only performance, but weird stuff starts happening in your OS.

Just one question though, is one of the SSDs an mSATA? The M17x R4 uses a HM77 chipset, which only supports up two SATA III ports. These ports are the main HDD ports, the mSATA runs on SATA II. If so, A good alternative could be to install the OS on the main SSD, then use the mSATA as a caching device for your storage HDD.

 

Thanks! I'll have to pick up another Samsung 830 and test this out. I didn't think it would make much difference since I've raided HDD's of different brands before and it was still a big boost over a single drive.

 

Yes, I have one Samsung 830 on the MSATA slot which is SATA II, but isn't SATA II bandwidth big enough to handle a single SSD?

 

I found a good article for setting up dual SSD RAID Stripe 0 arrays:

[M] RAID 0 Stripe Sizes Compared with SSDs: OCZ Vertex Drives Tested

I wish Dell would have the foresight to make the MSATA slot a SATA 3 port since the only devices it will take are SSD drives.

And another one:

Interesting...only the sequential read performance of the Crucial M4 series comes close to saturating the 6Gbit/s pipeline of SATA III. Most still fall within SATA II's pipe.

http://www.tomshardware.com/reviews/msata-ssd-review,3286.html

But, even if my SSD's are only running at SATA II speeds, it should still show almost 2x the performance of two SATA II SSD drives?

 

Okay, I went out and bought a second Samsung PM830 64GB SSD drive and ran a few tests.

The first test is with a stripe size of 16kb:


This test is with a stripe size of 32kb:


This test is with a stripe size of 64kb:


This test is with a stripe size of 128kb:


Last thing I noticed that's weird, CPU-Z is identifying a different CPU than what Windows 8 is identifying?


It's also showing HM77 chipset?


I hope CPU-Z is right on both accounts!

Overall, there's not a whole lot of deviation between stripe sizes, but it still doesn't look like it's running the way 2 x SATA II SSD's you think would run?? This is really baffling!

 

So both the ssd's are running in the hard drive ports now? You cant have one of them in the dvd slot or MSATA port. Sata 2 only allows for 300mbps. If either of those drives is in a sata 2 port the MAX throughput you can achieve is 600mbps. you must have your SSDs in the two hard drive ports. your results look like one drive is not where it should be.

 

Correct! I have one SSD in the MSATA port and the other SSD in bay HDD1.

That makes sense now, SATA2 max is 300mbps, so 2x that would be 600mbps. So, I guess the RAID controller is running both SSD's at SATA2 speed?

And when I tested a single SSD drive, it was in the HDD bay, so that explains why its performance was so close to 2 x SSD running in RAID0...because the HDD bays are SATA3 and SATA3 is 600mbps.

I guess the only way to run 2x sata 3 SSD's in RAID0 is to install them in the HDD bays.

And then I'd have to move my 2 x 1.0tb HDD's into the optical bay like this: http://forum.notebookreview.com/ali...al-hdd-m17xr3-using-mini-pci-e-raid-card.html

Really a waste of the MSATA slot since it's only SATA2.

I really hope that in the R5, Dell swaps one of the SATA3's from the HDD bays with the SATA2 of the MSATA slot. Or better yet, put in 2 x MSATA slots with SATA3 and leave SATA2 on the HDD bays. 1tb 7200 rpm HDD's now exist and I doubt those will ever saturate SATA2.

Users will be able to max out their laptops with 2 x MSATA SSD's at SATA3 + 3 x 1tb 7200rpm HDD's at SATA2. That's the ultimate in future upgradability.