The fstab discard option is required.
Ext4 is capable of issuing TRIM commands but it's turned off by default. The discard parameter turns it on. Without it your drive won't automatically erase blocks (prefill them in the background with binary 1s) when the blocks are no longer needed by the file system. There may be an initial performance hit by turning it on *if* your system is running disk intensive apps such as databases, but the payback is faster write speeds in the long run. If you don't use the discard option then when the file system writes to a non-empty, unused block the SSD must read the whole block and erase it before it can be written to; it's this bottleneck that the TRIM command is intended to overcome.
I also recommend shrinking the first partition on a SSD by about 10% of the total drive capacity (120GB SSD = 12GB free) and leaving the space completely unused and unpartitioned. The SSD's logic board should see that empty space and use it for spare blocks in case of damage and also as additional cache when it's been given a massive file to choke on.
Mint Testing Team & Mint Donor #3606
KDE 4.14.2, custom preemptive kernel 3.16.5,
Intel i7 4820K @ 4.7GHz, 32GB Corsair Vengeance Pro
3122MHz XMP, 4 Samsung 840 PRO 512GB SSDs in
RAID0, 6TB HW RAID10, 3 x 24" Samsung UlHD,