Why does my ZTE Score have so much trouble emulating video game consoles + games?

I have an ARM v6 600 MHz revision 5 CPU with 512 MB RAM. The GPU is an Adreno 200 with 245 MHz clock speed. It seems that anything in the 3-D realm, including some 2-D games, have trouble emulating perfectly smooth. I realize that 600 MHz CPUs are pretty poor these days, especially single-core and with dated microarchs. Some emulators also exhaust the CPU. My question is, is this ability to perform emulation based more on the hardware or software on Android-powered devices? It has to be a little of both, but I'm using Gingerbread. Do any newer Android OSes have better demand, or am I limited solely by the CPU?