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BARE FEATS LAB - real world Mac speed tests

One x16 PCIe M.2 board with four SM951 AHCIs = 5900+ MB/s

Originally posted November 9th, 2015 by rob-ART morgan, mad scientist
November 12th, 2015, added NVMe versus AHCI clarification near end of article.

Our readers have been frustrated by the inability to get more than 1500MB/s from Samsung SM951 AHCI flash blades mounted in slots 3 and 4 of the 2009-2012 Mac Pro tower. The x16 slot 2 has not been a helpful -- until now. One of those frustrated readers turned us on to a new x16 PCIe M.2 carrier board by Amfeltec in Canada. We obtained a sample which we populated with four SM951 AHCIs. After striping them (RAID 0), we ran our storage benchmarks.

GRAPH LEGEND
SM951*4 = Amfeltec Squid PCI Express Carrier board for M.2 SSD modules with four 512G Samsung SM951 AHCI flash blades installed in slot 2 of a 2010 Mac Pro 6-core 3.33GHz
SM951*3 = Amfeltec Squid PCI Express Carrier board for M.2 SSD modules with three 512G Samsung SM951 AHCI flash blades installed in slot 2 of a 2010 Mac Pro 6-core 3.33GHz
SM951*2 = Amfeltec Squid PCI Express Carrier board for M.2 SSD modules with two 512G Samsung SM951 AHCI flash blades installed in slot 2 of a 2010 Mac Pro 6-core 3.33GHz
SM951*1= Amfeltec Squid PCI Express Carrier board for M.2 SSD modules with one 512G Samsung SM951 AHCI flash blade installed in slot 2 of a 2010 Mac Pro 6-core 3.33GHz

LARGE SEQUENTIAL TRANSFER TEST
We used AJA System Test to benchmark file level sequential transfer speed using a 16GB test file (and 4K frame size).
LONGEST graph bar means the fastest overall in Megabytes per Second.

DIRECT SEQUENTIAL TRANSFER TEST
We used the Custom Sequential Direct I/O test in QuickBench.
LONGEST graph bar means the fastest overall in Megabytes per Second.

SMALL RANDOM TRANSFER TEST
We used a range of 4K to 1024K blocks in the Standard Random test in QuickBench as a predictor boot volume 'house keeping' performance and a simulation of an application that does multiple small random transfers.
LONGEST graph bar means the fastest overall in Megabytes per Second.

INSIGHTS
These transfer speeds of the Amfeltec Squid PCI Express Carrier board with four Samsung M.2 SM951 AHCI flash blades are the highest we have ever recorded on any Mac. It accomplishes this feat by taking full advantage of the x16 bandwidth of the #2 slot in the Mac Pro tower. And even with four SM951 AHCIs, it does not encroach on the adjacent slots. (In the photo below, the Squid card has room to breathe between the GTX 980 Ti below and another M.2 card above.)

But does it boot OS X? Yes. We installed OS X 10.11.1 El Capitan on the 4xSM951 AHCI 2TB volume. It definitely boots. However, the OS X installer warned that the resulting volume would not support FileVault or Recovery Partition.

What about heat? We ran our storage stress test (constant recycling Blackmagic Disk Speed Test for several minutes). The sensors of the four SM951 AHCIs reported high temperatures of 158F, 160F, 158F, and 165F. Those are right at or just above the recommended maximum of 158F by Samsung. But those temperatures are significantly lower than the 174F reported when the SM951 AHCI was mounted on other M.2 PCIe boards without heatsinks. One reason the Amfeltech Squid board runs cooler is likely due to the method of mounting the SM951 AHCIs that leaves an air gap above and below, allowing the PCIe bay inlet fan to do a better job of keeping the SM951 AHCIs cool.

NVMe versus AHCI flash? You may have noticed that we put "AHCI" next to "SM951" throughout this article. That's to bring to your attention that OS X does not support external, third party NVMe flash blades. However, a driver is available from MacVidCards that provides support for NVMe blades on all models of Mac running OS X. CAVEAT: MacVidCards states "...you will only be able to use (NVMe) drives for storage of data. You will most likely never be able to boot off of them, certainly not into OS X..."

When it comes to the Mac Pro tower, the NVMe blades won't run any fastet than AHCI blades since the PCIe 2.0 x4 slots top out at 1500MB/s. Even in the case of the Squid card in the PCIe 2.0 x16 slot 2, each individual blade is limited to 1500MB/s. The 5900MB/s is achieved through multiplication via the PCIe switch.

Armed with the Amfeltec Squid PCI Express Carrier board with four Samsung M.2 SM951 AHCI flash blades and the ASUS GeForce GTX 980 Ti overclocked GPU, our 2010 Mac Pro tower has been transformed into a 'beastly hot rod.' All that's missing are the flames and exhaust pipes.

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WHERE TO BUY THE AMFELTEC SQUID PCIE EXPRESS M.2 CARRIER BOARD

  • Order from Trans International
  • Order bare board direct from Amfeltec (mention "BAREFEATS" and you might get a discount)
  • Watch this page on RamCity's website. They will soon have stock of the Squid board.

WHERE TO BUY SAMSUNG SM951 AHCIs

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copyright 2015 Rob Art Morgan
"BARE facts on Macintosh speed FEATS"
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