SSD in MP 5.1... not expected results

JMVB

macrumors regular
Original poster
May 16, 2016
128
20
I have the MP 5.1 of my signature.
It had a Crucial M4 512gb SSD

And I have the MBP 15@ of my signature.
It had a Crucial MX100 512 SSD

Both with Yosemite 10.10.5

For curiosity, I did a Blackmagic speed test

The MP about 250 mb/s in read and write :/
The MBP about 510 mb/s in read and write :O

I'd a research in the net and right, the MX100 is faster than M5
Ok, i'll swap the disk, I think to myself

Back up both SSD, swap it and clone it

The MP 260 mb/s in read and write.
The MBP 260 mb/s in write and 510 mb/s in read...

Ok, clean installation, I think to my self

And.... the same result, 260 mb/s in read and write.

Why the MP have worst performance than less powerful laptop?

The SSD is in the 1º slot, and I have a 1 TB HD in the 2º slot and a 2 TB HD in the 3º slot
 

JMVB

macrumors regular
Original poster
May 16, 2016
128
20
ok, that was fast...

So, my results are ok?
 

throAU

macrumors 604
Feb 13, 2012
6,739
4,374
Perth, Western Australia
ok, that was fast...

So, my results are ok?

Well "OK" is subjective.

Are they fast enough for you? Because it's all you're going to get with that setup.

SATA 2 tops out at 3 Gigabit/sec. Which is a theoretical 300 megabytes/sec without any protocol overhead. Real world throughput is what you are seeing, SATA3 is 6 gigabit and tops out around 500MB/sec, which is what you see in the more recent Macbook.

You are entirely storage controller throughput limited. Your only options from here to get faster are to get a SATA 3 PCIe card (or M.2 card, no idea if either option is supported by OS X or not though), or run a PCIe SSD. Or run RAID with multiple SSDs.
 
Last edited:

h9826790

macrumors G5
Apr 3, 2014
14,504
7,033
Hong Kong
100% normal, as the others pointed out, the SSD is caped at the SATA 2 speed, which is around 250MB/S in real world.

If you didn't feel any problem in real world usage, that most likely means everything is OK.
 

Draeconis

macrumors 6502a
May 6, 2008
970
264
You are entirely storage controller throughput limited. Your only options from here to get faster are to get a SATA 3 PCIe card (or M.2 card, no idea if either option is supported by OS X or not though), or run a PCIe SSD. Or run RAID with multiple SSDs.

SATA-III and M.2 via PCIe adapter totally compatible. With M.2 ensure the SSD is AHCI though; some cards (SM951-NVMe, Samsung 950 Pro, Intel 750 series) use NVMe, a new storage protocol that Mac Pros don't support.

One chap did post a generic NVMe storage device driver, but this stopped working with more current OS X releases, he hasn't been around to offer a fix, and this still wouldn't allow it to be a boot device.
 

JMVB

macrumors regular
Original poster
May 16, 2016
128
20
It is there other sata iii option without using a pci-e slot?

I have not empty splots... I need it all..

SATA-III and M.2 via PCIe adapter totally compatible. With M.2 ensure the SSD is AHCI though; some cards (SM951-NVMe, Samsung 950 Pro, Intel 750 series) use NVMe, a new storage protocol that Mac Pros don't support.

One chap did post a generic NVMe storage device driver, but this stopped working with more current OS X releases, he hasn't been around to offer a fix, and this still wouldn't allow it to be a boot device.
 

DPUser

macrumors 6502a
Jan 17, 2012
935
232
Rancho Bohemia, California
You probably won't notice the difference in boot drive applications, since reads are very small and SSD is the limiting factor. Large file read/write is another matter.
 

flowrider

macrumors 603
Nov 23, 2012
6,255
2,384
Your results are as expected. My results on a cMP 5,1:

1. SSD in SATA Bay


2. SSD in Apricorn Velocity Duo


3. SM951 on WINGS PX1


Lou
 

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scott.n

macrumors 6502
Dec 17, 2010
337
78
There are USB 3 + SATA III combo cards, though I don't have personal experience with using one in a Mac Pro.

If one of your existing cards is an USB 3 card, then you could consider swapping it for a combo card.
 

h9826790

macrumors G5
Apr 3, 2014
14,504
7,033
Hong Kong
Well you could possibly use the Mini PCie slot where the Airport card is, but then then no wifi if you needed that.

That's a PCIe x1 Gen 1 slot, only 0.3GB/s bandwidth, Exactly the same as the SATA 2 slot bandwidth. Impossible to make it SATA 3.
 
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