Well it would help if you filled out what kinda of hardware you have.
A 920 is older, but can still be effective. I had a 960 up until last year and gamed just fine with it. Oc'd it a lil bit and even used 2 7970's in cf with it.
It really just depend and what you are tryin to do and why do you feel you need and upgrade. Are you hitttin some sort of wall?
A good upgrade for my 960 was an ssd, i brought new life into that rig.