[i.am]

A bigger ssd actually preforms better, if you don't need all the space then leave some unformatted (format 90-100GB of a 120GB drive)
SandForce controllers and newer will take note of unformatted space and will use this together with trim to increase performance significantly.

is it the same thing as partitioning into 2 partitions (say 90GB for OS etc, 30GB for data) ? or just leave the rest of the space unformatted?

[RaggSokk3n]

Uformatted
If you read about ssd architecture you will find that they can only delete "sectors" of data - they are incapable of deleting a single file. Therefore they fill sectors with dead/deleted data until they fill the entire sector. When the sector is full the ssd deletes the data in the entire sector. So with more unformatted storage you have more free sectors and the ssd therefore has more breathing room.
(won't show in benchmark but very noticeable with even normal use)
That's at least one of the reasons why ssd with more "unused" space will perform better.

[i.am]

Uformatted
If you read about ssd architecture you will find that they can only delete "sectors" of data - they are incapable of deleting a single file. Therefore they fill sectors with dead/deleted data until they fill the entire sector. When the sector is full the ssd deletes the data in the entire sector. So with more unformatted storage you have more free sectors and the ssd therefore has more breathing room.
(won't show in benchmark but very noticeable with even normal use)
That's at least one of the reasons why ssd with more "unused" space will perform better.

hey RaggSokk3n .. i have already installed ubuntu on all the drive.. when i wanted to reformat it (boot up from the disk), i see that the current partition is around 116GB for the OS and 4GB for linux-swap... how do i set it up so that i have some 'unformatted' space like you mentioned ..

[RaggSokk3n]

you just delete the old partitions and make new ones like 90GB os 10GB swap.