RAID 0 SSD speed identical to single drive

ghost.florian · 16 Apr 2015 at 10:25

Hello,

I recently purchased a pair of Samsung 850 EVO 120GB SSDs to install on a RAID 0 configuration on my system (see description below).

After I installed a fresh copy of Windows 8.1 and installed all drivers (including Intel RST) and updates, I started running some benchmarks to glow in the magical light of (hopefully) 1 GB/s read speeds.

However, imagine my shock when both Atto and CrystalDiskMark were showing the exact same speeds I would expect out of a single 850 Evo, namely around 550 MB/s read and 520 MB/s write.

The RAID array is visible in Intel RST, and both drives are fine according to CrystalDiskInfo.

Can anyone please tell me what is going on ? I tried searching forums for a similar problem but couldn't find anything.

ED209 · 16 Apr 2015 at 11:02

is the intel RST drivers up to date? make sure they are on the latest version and see is that helps.

ghost.florian · 16 Apr 2015 at 12:21

They are up to date - I downloaded them from the Intel website.

My motherboard BIOS is also up to date.

ED209 · 16 Apr 2015 at 12:26

may sound silly but are they connected to the sata 3 ports rather than sata 2?

I had 2 x 840 evos in raid on sata 2 and I was getting the same speeds (my sata 3 ones are marvell controlled and poor). also is achi enabled on the sata ports in the bios?

this can be easily be checked using the magician software but this doesn't work at all when the drives are in raid setup as the software cant detect them

ghost.florian · 16 Apr 2015 at 12:29

The MSI Z97 Gaming 5 does not have any SATA 2 ports. They are all SATA 3.

http://www.msi.com/product/mb/Z97-GAMING-5.html#hero-specification

Furthermore, RAID will not work if I set the SATA controller to AHCI. From what I understand, if I set the SATA controller to RAID then physical drives not part of the RAID array will run in AHCI mode automatically.

wazza300 · 16 Apr 2015 at 12:32

Did you check in the raid console that the drives are in an array? If not set them up

Press Ctrl and i at start up to enter raid console

ghost.florian · 16 Apr 2015 at 12:36

Yes they are - I set them up in the RAID console in the first place, and the console shows up just before the boot screen. They both appear to be member drives in the RAID 0 array.

Furthermore, Intel RST (software level) shows the two drives as being part of a RAID 0 array, and suggests everything is functioning normally.

ghost.florian · 16 Apr 2015 at 21:25

Here is a screenshot of the current setup, in case you need more details.

What I find odd is that the setup is faster than a typical 850 Evo and even an 850 Pro at the same size, but yet comes nowhere near the speeds you would expect from an SSD RAID 0 array.

Any suggestions ?

https://lh6.googleusercontent.com/-...AAJiQ/_zjW731sdK0/w1597-h851-no/SSD+Speed.PNG

Rroff · 16 Apr 2015 at 21:29

Could be hitting the controller's max (aggregated) throughput :S

ghost.florian · 16 Apr 2015 at 21:35

If this were the case, then how come this reviewer got 1GB/s with a Z97 chipset (same as my Mobo) ?

http://www.hardwaresecrets.com/article/Some-thoughts-on-the-performance-of-SSD-RAID-0-arrays/1876/3

These numbers were achieved with 2 PNY 120 GB SSDs, which should perform even worse than an 850 EVO.

BuToNz · 16 Apr 2015 at 22:37

If you go into Device Manager>Disk Drives and check the driver details on the RAID disk there. What is the date of that driver?

Had something similar myself a while back where I had old RAID drivers installed and even when installing the latest ones they didn't update. In the end had to update them manually (Force to use the right driver) as it wouldn't detect a newer one installed automatically.

ghost.florian · 17 Apr 2015 at 07:18

I think you might be right - the drivers seem to be from 2006. Where would I get the newest ones from, in a version which I can manually install ?

BuToNz · 19 Apr 2015 at 20:16

I think if I remember correctly they were in the Intel RST install folder. I pointed device manager there and it did the rest.