Some quick SSD benchmarks

Too wordy to put into Twitter.

Basically I just installed a 160GB Intel SSD 320 into my 2008 Mac Pro. Performance…  I really couldn’t tell how it was after enabling TRIM, but I felt like something was off after doing so.

By the way, for those of you with TRIM-supporting SSDs, you can bypass Apple’s arbitrary restriction on OS TRIM support by following the instructions HERE.

Using this, and later finding this page regarding benchmarks based on both the TRIM setting and the volume mounting option ‘noatime’, I decided to try the benchmarks myself since the settings were of interest to me.

Using the same settings in Postmark, namely:

set buffering false
 set size 500 100000
 set read 4096
 set write 4096
 set number 10000
 set transactions 20000

I ran the benchmark with the stock configuration, with TRIM but not noatime, and with noatime but not TRIM, and compiled everything.

The results are as follows:

SSD +TRIM -noatime
Time:
    17 seconds total
    12 seconds of transactions (1666 per second)
Data:
    557.87 megabytes read (32.82 megabytes per second)
    1165.62 megabytes written (68.57 megabytes per second)

SSD -TRIM -noatime
Time:
    16 seconds total
    11 seconds of transactions (1818 per second)
Data:
    557.87 megabytes read (34.87 megabytes per second)
    1165.62 megabytes written (72.85 megabytes per second)

SSD -TRIM +noatime
Time:
    16 seconds total
    10 seconds of transactions (2000 per second)
Data:
    557.87 megabytes read (34.87 megabytes per second)
    1165.62 megabytes written (72.85 megabytes per second)

And finally, in graph form:

In conclusion, it seems that (with Intel SSDs, at least) for best performance you’ll probably want to keep both TRIM and noatime turned off, at least until Apple gets its shit together and makes TRIM work better.

I saw TRIM lower throughput by around 6%, and transactions by around 9%. Noatime on its own was responsible for an additional gain of almost 10% in transactions per second!

I’m not sure if this affects stock Apple SSDs, but it might be worth trying to knock out TRIM and see how that affects performance, and I’m joining the growing crowd that recommends that noatime be enabled for any SSD – not just for longevity concerns (which may or may not be baseless), but because it hurts nothing, but improves the speed of operations.

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