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Why a slow write speed from a Crucial P2 upgrade?

D

Dsheridansc

macrumors newbie
Original poster
Jul 12, 2021
8
0
I installed a Crucial P2 with a Sintech NGFF M.2 nVME SSD Adapter Card on a Macbook Pro (Retina, Late 2013) with Big Sur 11.4. Read speeds from BlackMagic are a barely higher than the original Apple SSD (~ 500MB/s) but Write speeds die quickly. The first numbers during the Write test are around 1000 MB/s but quickly drop to around 400 MB/s. On the second repeat of the Write test it stays at about 40MB/s from then on (about 10% of the original SSD). Am I using the wrong Sintech adaptor? I was following the article by maxthackray on Mar 1, 2017.


Hardware Overview:
Model Name: MacBook Pro
Model Identifier: MacBookPro11,2
Processor Name: Quad-Core Intel Core i7
Processor Speed: 2 GHz
Number of Processors: 1
Total Number of Cores: 4
L2 Cache (per Core): 256 KB
L3 Cache: 6 MB
Hyper-Threading Technology: Enabled
Memory: 8 GB
System Firmware Version: 431.0.0.0.0
SMC Version (system): 2.18f15
Serial Number (system): C2QMH02ZFTPL
Hardware UUID: 498D1247-B8F0-5F30-B854-DE3E1B9DCDEC
Provisioning UDID: 498D1247-B8F0-5F30-B854-DE3E1B9DCDEC
 
When I did a BlackMagic Stress of 1 GB files, the Read and Write speeds were both about 1000 MB/s. But a 2GB test fell off on Write speed.
 
Hear is a screenprint of the NVME settings.
Screen Shot 2021-07-13 at 11.37.31 AM.png
 
I've run across a similar problem with a P2, 2 TB SSD in a Sabrent M2/NVMe USB-C/3 enclosure. I really like the Sabrent. Looks good, and seems well-made. But... it takes at least 8 seconds to mount the P2 (HFS+ Journaled) and often more. Aja and BlackMagic both report wild swings in speed from 50 MB/sec. or 250 MB/sec., where it often settles. Rarely do I ever get in the realm of 400 MB/sec. I have 4 brand-new Sabrent cables and they all do the same. The P2 also reports the same speeds in a second, identical case.

Placing a Mushkin MKNSSDHL 1TB-D8 NVMe SSD in either enclosure, with any of the cables, immediately mounts in less than 1 sec. and it benchmarks consistently over 400 MB/sec. Again, I don't need it in anything but an external drive on a USB-3 "legacy" 2011 iMac...for now.

Placing the P2 inside a 2015 MacBook Pro (it fits nicely, even with the M2 adapter,) the P2 benchmarks at a respectable, but rather sedate 1700-2000 MB/s read & write, but I need it in an external and the P2 just throws up in that role.

A Crucial support chat rep (clearly non-native English speaker) asked me the same questions that I'd already provided three times, and then said nothing was wrong. As it works internally, I get it, but its chipset is not playing nicely with the Sabrent, or the OP's Sintech, either. There's a 2 TB Mushkin (MKNSSDPE2TB-D8) that I'll probably get, and it is cheaper.

Oh, Sabrent support was fast and helpful. They think it might be the Crucial chipset as the Mushkin uses Phison’s E18 controller. Don't know what Crucial uses, but I'm not going to find out. It doesn't work for me. My 20+ year, near-exclusive run with Crucial may be nearing a close.
 
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Further datapoint: Mushkin MKNSSDPE2TB-D8 benchmarks fast and stable in both r/w (using Aja, Blackmagic, Sensei) in the Sabrent NVMe enclosure. Also seems somewhat reliable in copies. Yes! Unfortunately, it is also reliable when it disconnects after 20–30 minutes of copying a large 2 TB photo library. As it got hot, I put a fan on it and tried again. Stayed cool, but still disconnected. Tested formatting with both HFS+ and APFS using USB-C to USB-3 Sabrent cable(s) under Mojave and Big Sur (both fully updated) on two different 2015 MacBook Pros. All the same.

So... Either the P2 broke the Sabrent, or neither drive plays well out-of-the-box with the Sabrent enclosure/chipset. I think the latter as the P2 continues to operate, though inconsistently, just as it always has when I swap it with the Mushkin.

Sabrent's support continued to be responsive and offered small, but useful, tidbits of assistance. However, they ultimately did not want to escalate me to Make It Work™, or determine any problem. They were happy to help get it replaced, but I still have an open window from Amazon, and I will take the refund, as it just doesn't seem to be proper time for convergence of the heavens with this particular use-case for me. I'll have to spend more to get less (something like the Crucial X8) that won't transfer as well (no big speed increase) to a newer rig later, but as I don't plan an upgrade any time soon...
 
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