I have a Vertex Plus r2 OCZ SSD drive in my Macbook Pro 2010,

It's been going well and it only cost me like 80gbp.

I noticed recently (not that I run tests regularly) that the performance has dropped by nearly 50%

200Mbps read -> 90, 160 write -> 80

There is so much misinfo on SSD's out there it drives me mental, I don't have the 'trim enabler' hack installed because I read that the SSD drive had it's own built in hardware regeneration/ware leveling/trim type thing going on.

My question: how can I get performance back to what it was like when I bought it (6 months ago).

I was thinking:

A) Enable trim? B) do a complete format and reinstall? C) Leave the computer on and idle and hope it does it's hardware trim thing or whatever?

Any thoughts?

Thanks, John


Try erasing free space (from Disk Utility, on the bottom left corner of the "erase" tab of your drive), and then enable trim (via Trim Enabler).

More than likely this drop in performance is caused by the SSD having to clear memory before being able to write to it. Flash memory can only bring bits up (from 0 to 1), meaning that over-writing a non-zero byte requires first erasing the whole byte, then bringing up whatever bits are needed. This means that 2 operations are needed (erase, write) rather than just 1 (write). TRIM helps improve performance by actively zeroing out memory locations that have been deleted during idle times, allowing for a single write operation to be sufficient for writing to that location. Erasing free space will do the same thing, but it's a one time deal, whereas TRIM works in the background to keep it all tidy.

  • Good suggestion,seems like Erase free space is greyed out, discussions.apple.com/thread/3210131?start=0&tstart=0 -- apparently on purpose!, is erasing free space really all trim does? if so would a complete format and restore do the same thing? also how would this explain the drop in read speed. finally what about the hardware trim thing is that not working? thanks!! – Woodstock Sep 14 '13 at 20:29
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    Hmm it appears to be a disabled feature for SSDs, probably because the OS assumes TRIM is active so it isn't needed. diskutil secureErase freespace 3 /Volumes/[name-of-drive] shouldn't fail you though – Alexander Sep 15 '13 at 0:12

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