Unallocated Space on SSD

Hi, I just bought an intel 180GB SSD and while creating the partitions I accidently left 20GB of unallocated space.

Is it okay to leave the space there? I'm worried about unevenly wearing the SSD

 

It doesn't matter how much you partition or leave unallocated. At some point, the SSD will use ALL available NAND cells to do its thing.

...even if you’re using only 60% of your drive, chances are that 100% of your drive will get written to simply by day to day creation/deletion of files.

 

That unallocated space you left will be treated as spare area. And it will increase endurance.
If it was me, I would have left 36Gb unallocated .

 

He's likely OK with 20GB unallocated with a SSD with nominal 180GB of space; that's 11% unallocated together with whatever spare space the SSD already has set aside.

An odd nominal size of 180GB likely has unstated spare area set aside.

I'll like SSD drives a whole lot better when they start stating upfront how much spare space is set aside as unallocated space!!!

 

He is OK with that, no probs.
Again. if it was me, I would have left 32Gb unnallocated for 180Gb that is 17% + (probably 6.88% reserved for spare area).

 

In either a same (capacity-wise) free space or 'unallocated' condition: sure all nand will be used.

The difference is that in a simple free space setup; all the nand will be 'dirty' at almost all times. This will give the dreaded read/update/erase/write cycle that not only needlessly burns through the nand cycles (increased Write Amplification (WA), but also gives the lowest and most inconsistent performance the SSD (controller/nand combo) can give.

While in the 'unallocated' setup; the nand will be cleaned, primed and ready to work (at our command) giving the most performance possible with the least WA.


The thing to remember about over-provisioning is not that it increases the performance of the storage sub-system (even if it does in terms of consistency) - but rather that it prevents the SSD from going into an out-of-control tail-spin that only a SE (secure erase) would be able to make it perform at the speeds it is capable of.


In my experience (even if Anand recommends at least 25%) - I have found that 30% over and above any other built-in spare area/over-provisioning is the best balance of capacity 'lost' vs. performance gained.

This is the calculation I use to find that 'magic' 70% of any SSD's capacity:

Example SSD 'nominal' capacity: 180GB...

180 x 1000 x 1000 x 1000 = 180,000,000,000 bytes (advertised capacity).

180,000,000,000 / 1024 / 1024 / 1024 = ~167GB actual capacity available.

167 x .7 = ~117GB actual capacity available with 30% over-provisioning accounted for.


Note:
To get more accurate numbers; use the total MB's available in the Windows 7 or Windows 8 custom setup (drive) options - not that this matters, but SSD's just like HDD's are not all 'equal' with how much actual available space is shipped. What the Win7/8 setup options show is the actual available for your drive - take that number and multiply it by 0.70.




While it is true that an SSD's controller will ensure that ALL nand chips be used as equally as possible (whether in a used, free space or 'unallocated' state) and therefore it can't 'wear' unevenly - it is also true that 'unallocated' capacity is superior to simple 'free space' when WA, GC TRIM and sustained, performance over time (consistency) is also taken into consideration.

 

The free gparted program (bootable) also gives accurate GiB numbers for partitions.

For GiB see: Gibibyte - Wikipedia, the free encyclopedia

For gparted see: GParted -- About

 

Thanks for all the informative replies. I'm glad now that I left some space when partitioning. 70% gives me plenty of space for programs and games and I shall keep all data and media in my HDD.

 

The disk management utility should allow you to take advantage of that space. If not, don't worry, it's not harming anything.