Poor graphics performance.

[Dregel]

Hello!
I was in the process of turning my Raspberry Pi into something like a HTPC, used mainly for playing videos and emulating old game consoles, such as NES, SNES, GameBoy variants, Sega Mega Drive/Genesis, and such.
And I wanted to stay clear from "Out of the box" sollutions like Retropie och OpenELEC and opting to create my own front end for the "HTPC", in favor of the system control that Arch would give me.

So i got Xorg up and running openbox, just to start trying out emulators and such, but this is where i run into problems.
I have tried both AVB-M and FCEUX, but both run AMAZINGLY slow, down to about 1-10% emulation speed (Can't remember the exact speed, and I'm not home right now to check it).
I tried messing about with both the Xorg drivers and emulator setting, but nothing seems to help.

Any ideas?