I’ve just given [TRIM Enabler](http://www.groths.org/?p=461) a try out. Benchmarking the drive performance was not showing any significant performance degradation since the original installation, but it was just one of those things on the list to take a look at some time. Apple introduced TRIM support for Apple supplied SSD’s along with 10.7 Lion, but decided to not implement it for non-Apple SSD’s. I guess they just decided that there were too many variables to give blanket support without at least some additional testing, so I’d think that a future Lion update might broaden support.
In the meantime, TRIM Enabler makes turning on TRIM support simple. The original hack to enable support required HEX Editing of the relevant library extension, but this is not for the fainthearted, and thankfully someone came up with a simple patch utility. Although TRIM Enabler contains its own backup option (which you should run BEFORE applying the patch), I’d recommend making your own copy of the relevant file (/System/Library/Extensions/IOAHCIFamily.kext) just to be on the safe side. In theory, if you have Time Machine backing up your drive, you could rely on that for a backup.
I’ve two systems, a MacPro1,1 (2006) which has 4 conventional data drives in a RAID 10 array, and an OCZ-VERTEX2 128GB SSD as the system drive. The second system is a Macbook2,1 (also 2006) which uses an OCZ-ONYX 128GB SSD as the system drive.
I first tried TRIM Enabler on the Macbook – the patch appeared to work as intended, and System Profiler reported that the SSD now had TRIM support. The system appeared to boot without issue and general performance appeared fine. I then tried running XBench to get a Disk Benchmark and compared it against one I’d saved when I installed the SSD. Unfortunately, the read and write performance was probably half of what it had been originally. Others using TRIM Enabler had reported similar problems although I couldn’t find specific mention of anyone using an OCZ-ONYX drive. I decided therefore to restore back (again using TRIM Enabler). Interestingly TRIM Enabler didn’t seem to like the backup it had created (I couldn’t select it) but it offers a ‘default’ option so I used that. I rebooted the system, ran XBench again and the performance was restored to what I would expect. Therefore, it looks like TRIM support on an OCZ-ONYX drive is not compatible and causes performance issues.
I then tried the patch on the MacPro, and XBench reported performance on a par with its original performance, so it looks like on the OCZ-VERTEX2 drives, TRIM support compatibility is good. I’ll continue to monitor performance, and report back if there are any changes.