Heh, and now I just noticed your earlier message had this:

  When running games on windows I used iscsi for my games, and that worked well ...

Ahhh well. If you want to try iSCSI for the Linux side of things too, then the above might help. :)

Using an ssd pool on the nas will be your best bet though. With a 10GbE connection it'll feel like a natively attached ssd, which sounds like it'd be a massive improvement for you. :D