how much space to leave free on ssd?

happle

macrumors 6502a
Original poster
Jun 20, 2010
501
0
i have a 128gb ssd which has about 120gb available for use. iv heard that you need to leave a decent amount free on ssds to keep them healthy. about how much should i keep free to keep this baby working for a long time with no slow downs?
 

GGJstudios

macrumors Westmere
May 16, 2008
44,419
756
With any drive, HDD or SSD, you should leave at least 10% free space. More is better.
 

dusk007

macrumors 68040
Dec 5, 2009
3,386
61
Part of the SSD stays "free" anyway. It is called over provisioning and all modern SSDs do it afaik between 10-30%.
Thus even if you use your SSD 99% for weeks it shouldn't have any problem as it technically isn't full yet but still has some extra space that you cannot use up.

There is no need to keep 30% free. It is simply really annoying if you always run out of space and there are quite a few programms that simply crash if the hdd tells them it is full, thus you should always strife to keep around 10% free so you don't run into such troubles.
 

mkrishnan

Moderator emeritus
Jan 9, 2004
29,777
12
Grand Rapids, MI, USA
Part of the SSD stays "free" anyway. It is called over provisioning and all modern SSDs do it afaik between 10-30%.
Thus even if you use your SSD 99% for weeks it shouldn't have any problem as it technically isn't full yet but still has some extra space that you cannot use up.
I didn't know much about how this works, FWIW, so I found this:

http://www.micronblogs.com/2009/04/overprovisioning-give-a-little-get-a-lot/

(FWIW, they also comment, that as of last June, see the comment from the original poster at the bottom, only their enterprise products, which are marketed at 50/100/150/200GB sizes instead of powers of 2, are overprovisioned.)
 

dusk007

macrumors 68040
Dec 5, 2009
3,386
61
I thought they all do but you are right the C400/M4 doesn't use any over-povisioning and it is not a good thing. Intel does use just 3.4% which isn't much either with the same controller but suffer much less.
The controller doesn't need a whole lot as it seems but still one should probably just try some manual over-provisioning in that case of a few percent.
When creating the partitions if one leaves a few % like 3 unassigned those go to over provisioning.

Yet still even in the worst case all filled up the drive is vastly faster than any HDD in the best case and you would never ever feel the difference in normal use as in snappiness and stuff. Some transfers might slow a bit.
http://www.tomshardware.de/intel-ssd-320-crucial-m4-realssd-c400,testberichte-240760-4.html

It certainly doesn't need 30% though.