
Mac SSD performance and TRIM in OSX - soundsop
http://www.bit-tech.net/hardware/apple/2010/07/01/mac-ssd-performance-trim-in-osx/1
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m_eiman
Does the SSD really treat overwriting everything with zeroes as a low level
format? I'm guessing "no", and that the entire test was performed on dirty
disks.

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mkramlich
that struck me too. he pretty much said early on they were doing the tests on
a _used_ computer given to them by the vendor. a box that had previously been
given to other reviews to test/review. therefore, I don't see how he can truly
know for sure whether or just how clean/virgin that SSD is.

~~~
m_eiman
Not only that, he explicitly filled the drive with zeroes using Disk Utility.
He probably should have run HDDerase (or a similar utility from Samsung, if
available) from a bootable USB stick to clear it instead.

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Murkin
There is a reason why there was no performance degradation: They ran the tests
on "dirty" disk both times.

To clear an SSD, specials methods must be used: They are vendor specific but
the SECURE ERASE command (ATA spec) will mostly do.

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sramov
That is correct. They just wrote data over the whole damn disk. ATA SECURE
ERASE as I believe directs the controller/firmware to bring the cells to a
factory state, which takes a little time because the cells only need to be
marked clean, not rewritten or anything like that.

The method I use on my SSD when reinstalling:

    
    
        hdparm --user-master u --security-set-pass 12345 /dev/sda
        hdparm --user-master u --security-erase 12345 /dev/sda

~~~
Murkin
Actually each cell (each bit) is reset to an initial state.

It is still blazingly fast, as the erase is:

    
    
      1) Done in large chunks
    
      2) Done in parallel (most SSDs have multiple dies)
    
      3) Does not require data transfers out of the drive.
    

The ERASE also resets the internal data structures (dirty/etc lists).

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BSousa
I have a MacBook Pro from last year with the Intel X-25 SDD and I can attest,
on real life (not benchmark programs) the hdd grows slower (more noticeable on
Spotlight and Safari). I even have a ram disk for most scratch operations
(compiling code for example) but even so, after a few months of use, the sdd
needs a good wipe (hdparm does the trick).

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ComputerGuru
I just bit the bullet and bought a 700 dollar SSD for my MacBook (which is
over half the price I paid for the MacBook Pro itself!)

It's really hardest on the wallet for us laptop users. On the desktop, you can
get by with a 40GB+ SSD and a secondary traditional disk (in my case,
2xVelociraptors in RAID0). But on a laptop, you've got to shell out the extra
bucks for the largest SSDs on the market, because it's ridiculous to walk
around with anything less than 200GBs in your notebook these days.

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sjs
I just did the same, probably a similar disk. If you don't use the optical
drive much you can always add an SSD and keep your current disk with 320 or
500GB.

I think 240GB will be enough. If not I might end up replacing the optical
drive.

It's a lot, yeah, but the way I look at it is I just spent top dollar on a
shiny new notebook and using a rotational disk in it is cheating myself out of
a good investment. I couldn't justify not getting one any longer, even though
I know that winter will bring higher capacities and lower prices.

~~~
ComputerGuru
Exactly the same reasoning. I don't use my optical drive _at all_ (maybe twice
in 2 years??) but I just don't like the idea of castrating my MBP (funny,
because I had no such qualms about any of my old devices).

I got the C300 RealSSD: [http://www.amazon.com/Crucial-Technology-RealSSD-
Solid-CTFDD...](http://www.amazon.com/Crucial-Technology-RealSSD-Solid-
CTFDDAC256MAG-1G1/dp/B0039SM0B2)

I had been waiting for the F240 from Corsair to come out, and as I was
waiting, this one popped up on the market and it blew all the competition
away.

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sjs
Nothing new here. It's coming, just a matter of when and how broad.

All the reviews I've read regarding the Sandforce 1200 indicate that slowdowns
are not a big problem for that controller. They don't mention it in this
article, neither do they mention it in their test from February.

Just do your homework before buying a disk. It only takes an hour to check out
a few reviews.

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wmf
Ugh. As pointed out in the Slashdot comments, this article is not even wrong.

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daniel-cussen
tl;dr SSDs that run Windows need TRIM for a vast performance boost, but macs
either already have TRIM and are not advertising it or do not need TRIM
because of intrinsic qualities of the OS.

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neilc
... but only for the relatively ancient and poorly performing SSD that Apple
ships with the MacBook Air. Whether the results generalize to other SSDs, or
the reason for why there's no major performance degradation, are both open
questions.

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itistoday
Someone pointed me to the OWC Mercury Extreme Pros, which are extremely fast
and maintain performance without TRIM:

<http://macperformanceguide.com/SSD-RealWorld-Seasoning.html>

<http://www.barefeats.com/mbpp19.html>

I took the plunge and am quite happy I did.

