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jordanz

macrumors member
Original poster
May 13, 2012
91
45
Got a Crucial m4 256GB SSD in a 2011 Mac Mini.

It's been in there for years but for the past year or so I've had consistent shockingly bad speeds: max 50mb/s write, ~75mb/s read. I've had TRIM off since Yosemite or whichever OS it was that disabled third party TRIM support.

Upgraded to El Cap and used the "sudo trimforce enable" command in Terminal. Deleted a few unused apps totalling 5-6GB, waited a few mins, ran a blackmagic speed test again and bam! 265mb/s write, 498mb/s read.

Far cry from the newer Apple PCIe SSD speeds but much happier considering my older speeds. I read about degraded performance over time without TRIM but 75mb/s read to almost 500!? I honestly thought my machine was just getting old, didn't know a simple command could bring it back to life.

Hopefully this helps someone else with poor speeds on the fence about enabling TRIM.
 
Got a Crucial m4 256GB SSD in a 2011 Mac Mini.

It's been in there for years but for the past year or so I've had consistent shockingly bad speeds: max 50mb/s write, ~75mb/s read. I've had TRIM off since Yosemite or whichever OS it was that disabled third party TRIM support.

Upgraded to El Cap and used the "sudo trimforce enable" command in Terminal. Deleted a few unused apps totalling 5-6GB, waited a few mins, ran a blackmagic speed test again and bam! 265mb/s write, 498mb/s read.

Far cry from the newer Apple PCIe SSD speeds but much happier considering my older speeds. I read about degraded performance over time without TRIM but 75mb/s read to almost 500!? I honestly thought my machine was just getting old, didn't know a simple command could bring it back to life.

Hopefully this helps someone else with poor speeds on the fence about enabling TRIM.

Curious what did you use to do the speed test? Freeware?
 
TRIM is imho primarily a speed helper as with TRIM the deleted "blocks" of data on the disk device can be really erased asynchronously and are therefor ready to be written as soon as they are deleted. Without trim the data blocks are only logically deleted, but real deletion only occurs when the operating system wants to use the block for write operation again. In this case the blocks need to be deleted for real first before the actual write command can be executed and therefor one can see severe slowdowns without TRIM on solid state disks if used heavily over longer periods of time.
 
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