Strangely slow Velocity Duo X2 plus RAID 0 Samsung 850 Evos.

[IowaLynn]

I have read where just from installing to a SSD will suffer until TRIM is enabled AND repair the SSD booted from another system, with TRIM so that blocks can be TRIMMED.

Having TEA lone not being enough.

I use the XP941 in a 8x PCIe 1.0 slot (1,1)

 

[DEMinSoCAL]

I have read where just from installing to a SSD will suffer until TRIM is enabled AND repair the SSD booted from another system, with TRIM so that blocks can be TRIMMED.

Having TEA lone not being enough.

I use the XP941 in a 8x PCIe 1.0 slot (1,1)

I don't think TRIM is required to get basic, expected R/W speeds from SSD's. My dual SSD 4,1(5,1) with Velocity Solo x2 cards gets expected speed results and that is in 10.10 with NO TRIM. I also cloned my boot volume using disk utility to the RAID 0 set.

 

[IowaLynn]

I don't think TRIM is required to get basic, expected R/W speeds from SSD's. My dual SSD 4,1(5,1) with Velocity Solo x2 cards gets expected speed results and that is in 10.10 with NO TRIM. I also cloned my boot volume using disk utility to the RAID 0 set.

So you don't think TRIM helps? or that cloning versus installing, makes a difference?

Not "magical" but ARS posted an article on 27th worth a read.
http://arstechnica.com/gadgets/2015...garbage-collection-so-i-dont-need-trim-right/

 

[DEMinSoCAL]

The Duo and the 850's are only a few weeks old. The speed was the same when first installed. I've checked it many times under various conditions and it's always the same.

The only other device in the PCI slots is an MSI R9 280X, unflashed, but with the R17 resistor removed for 5 Gb/s operation. Perhaps I'll put my Apple 5770 back in it and try it then.

Thanks again.

Are you still within your return period? If so, you might consider what I did, and that is to go with TWO Velocity Solo X2 cards, where each Solo X2 has one SSD. This takes up 2 slots, but that isn't a problem for you. The benefit is that each card can reach a max of 800MB/s, instead of the DUO's max of 800MB/s for both SSD's. Since each of your Evo's should get >500, you could get to about 1000MB/s with your RAID 0 set. I get mid 900's with my RAID 0.

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So you don't think TRIM helps? or that cloning versus installing, makes a difference?

Not "magical" but ARS posted an article on 27th worth a read.
http://arstechnica.com/gadgets/2015...garbage-collection-so-i-dont-need-trim-right/

I'm not saying it doesn't help. Did you read my post? I said it isn't required because my own setup is TRIM-less AND I cloned AND I get maximum, expected speed from my SSD's. Simple.

 

[m4v3r1ck]

I would test each SSD, installed one at a time in a standard configuration. For example only one SSD, freshly formatted/Trimmed and installed physically on the DUO at a time. Perhaps one drive isn't working properly and dragging the other one down the rabbit hole.

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What is your stripe setting?

RAID Block Size: 32k

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Hi Maverick,

OK, I did the same except I didn't do a clean install, I cloned from my pre-existing OSX 10.9.5 Raid 0 disk array (in normal drive bays). This sort of thing has always worked well for me in the past, and I'm not sure how I'd consider that a likely culprit (it would be a pain to redo it at this point, too).

Can you confirm that in your 3,1 you were getting ~800 on BM?

Thanks.

I was getting ~700 on AJA

 

[Ph.D.]

At this point I'm going to assume that the performance I see is the performance I should expect. Just a few percent lower than Maverick reports, but higher than some others have reported. These SSD's are a quite different technology than most and it's not unexpected to see some differences in performance.

(As an aside, I don't think I can go to two Solo X2's, since I'll run into the PCIe 1.0 issue on slots 3 and 4.)

It does make me wonder if I should have stuck with two non-raided disks, but then the performance would still be ~30-50% or so lower per disk.

Eventually, true PCI-e SSD's (or whatever comes after that) will be mainstream. By then I'll quite possibly have moved to a nMP gen 2 or 3, and these SSD's will likely go in a backup chassis.

Thank you all.