Ssd 128gb only 91gb of Capacity?

They probably reserved some space for recovery purposes which is made inaccessible for you.

The restore partition is using some. Run command prompt as administrator and type "powercfg -h off" which turns off hibernation and will save you 4-8gb depending on the amount of RAM you have.

more than likely an older spec SSD which uses more space for over provisioning. Older drives often had extra space set aside to cover failures. That and you Windows installation is probably the main culprit.

What make / model SSD have you got

All SSD drives use over provisioning that is all that is going on here this is normal Thats why they sell 480 gig SSD drives. This is a 512 gig drive that has some set aside for nand failure. what happens is over time the nand cant hold a charge an the drive will notice this and change this sector to a good one in the spare nand set aside and the drive will continue working like nothing is wrong until all this set aside nand has been used. The issue is in the advertising, some sell you a 128 gig SSD and some sell a 90 gig SSD. Both have 128gigs of space but you only get 90... Sooo yeah

Thent

Well, right off the bat, you have the usual storage issue. As you correctly noted, 128 GB according to the manufacturer only translated to 119 GB when measured by the OS. However, the clue is in your "71 of 91 GB free". A lot of OEMs use a dedicated Recovery partition on the primary drive in place of the old physical discs; it saves on packaging, & GB storage is much cheaper on an SSD/HDD than on a set of CDs/DVDs. You can usually expect the OS to take up roughly 20GB on a drive, which means the recovery partition will also take up about that much space. And those are OS-measured GB, not manufacturer GBs. Sometimes, of course, the recovery partition may be even bigger.

So...in your case, fresh from the OEM you saw 71 GB free out of 91 GB available. That confirms the "20 GB for OS" rule...and points to your Recovery Partition measuring about 28 GB (119 GB - 91 GB = 28 GB), most of which would be the OS.

One way to double-check, is to see if there's a separate volume listed under My Computer (or whatever WIndows 8.1 calls it).

As for what your options are...you can always see about copying the Recovery partition onto physical DVDs, which might allow you to free up the space. However, I don't know how well those will work should you have to restore your PC, nor what might happen to any personal files (i.e. if it makes you blank the SSD to take advantage of the free space). Based on the brand (Lenovo), this is probably a laptop...which means the usual solution (adding a secondary HDD for additional storage) is probably not available. What you should consider is getting an external HDD (USB or eSATA, depending on what your laptop supports) to store the majority of your personal files -- homework assignments, photos, home videos, etc. -- that you a) don't use on a regular basis) and b) take up a lot of space. Also use it for programs that you use only occasionally, or that don't need the speed boost as much. Also, barring the installation of a larger SSD, you'll probably have to get used to the idea that you won't be able to install too many large apps (i.e. recent games) on the SSD, as they just take up too much space (if you only have 71 GB available, installing a game on your SSD that needs 60 GB of space for the uncompressed textures isn't very appealing).

your 128gb drive is probably actually 110gb, and with 10-15% reserved for future dying nand cells, 91gb sounds about right.