Intel Storage Controllers - AHCI, RAID, and TRIM

[bigdogchris]

I have a P67 board set to RAID mode. My SSD is by itself, along with 2 HDD's in RAID 1. I've always read that if you have an Intel storage controller set to RAID mode, that an SSD attached to the controller still receives TRIM commands, as long as it's not part of a RAID array. Today I don't think I believe that anymore.

1 - I've read something: "Users were led to believe that the Intel RST 9.6 drivers would add TRIM support in RAID volumes, but Intel later clarified that it was only for SSDs acting as single drives in AHCI mode alongside a separate array attached to the same Intel storage controller"

2 - I just bench marked my SSD with AS SSD and compared it to benchmarks done by two review sites. The benchmarks show my SSD read speeds are almost identical (and better in some cases) than the reviewers site. However, my write speeds are quite a bit slower (about 50%) on my drive than the ones in the review, using the same utility

Site 1.
Site 2.

What else would cause such massive write speed degradation? I'm comparing apples to apples here with both the utility and SSD.

I challenge any of you who have an stand alone SSD on an Intel RAID controller to run AS SSD and compare the write speeds to review sites that used AS SSD on your SSD version. Make sure you mouse over the drive on AS SSD to ensure it says "RAID". My board does not allow me to have the Intel storage controller in both RAID and AHCI for separate ports.

 

[Crotan]

Does your SSD have your Windows install? Were the review sites benching it as an additional drive?

 

[mwroobel]

Also make sure you disable any antivirus apps prior to the tests, they can put a nasty drag on write performance.

 

[bigdogchris]

I'm guessing they were benching it as a stand alone drive. Considering i'm idling, would the OS really make that much impact on write speeds? Wouldn't it also effect read speeds then?

I just ran Erase and wiped my freespace and ran the benchmark again. The write speed went up a little bit but it's still not close to the review sites. I also disabled my AV and it made no difference to write speeds.

 

[ckryan]

Do you have the Vertex 2 120 with 25nm NAND?

The V2 with 64gb, 25nm NAND are slower with incompressible data.

I don't have a vertex 2 120, but I do have a Vertex LE 100 (which has 128GB of NAND, but has 28% over provisioning -- though is otherwise identical to an original V2).

The benches you linked are using the original 34nm IMFT NAND equipped Vertex 2s. You didn't post benches of your own drive, but here is a pic of my writes speeds with Anvil Storage Utilities:

This was done with incompressible data, and with the drive as the OS drive (Using about 47GB). Max sequential writes with random data on my drive are 130MBs.

 

[bigdogchris]

I have the version that shows 111GB in Windows, which I believe is 32NM. It's the version that the case is sloped. These benchmarks are very similar to AS SSD's. Remember, this after I zeroed the unused space.

 

[bigdogchris]

I attached the SSD to another computer and benchmarked it again. The results were the same as before, with slow write speeds. So I decided to securely wipe it and benchmark it. Lo and behold:

So what this tells me is that the TRIM command is not being passed through RAID controller to non-member drives. I may have to disable my RAID 1 array and just use Windows Backup to keep the drives mirrored for me.