What is the best NES emulator for me?

I have tried many NES emulators and they all have slow, choppy gameplay. While I am not very computer-literate, I have determined through research, that the GPU on my computer is lacking. My computer, a Gateway SOLO 5300, is coming up on 14 years old.
ZSNES works great for me, but from what I have read, that is only because it uses low level code, whatever that means.
Is there an NES equivalent to ZSNES in terms of system requirements?

Unfortunately they are all about the same, the fastest would be nestical. Its a dos based emulator and very fast! Depending on your os, it may or may not be hard to run.

from what I have read, that is only because it uses low level code, whatever that means.

Click to expand...

Someone got that backwards? High-level emulation is for slower computers but also the latest technology.

Low-level, reads data from the game and tries to emulate chip by chip most accurately.
High-level is more like a wrapper to make the running game thinks its on a console. It uses tricks to skip math crunching operation so speed up or satisfy the results.

A true low level is more like the atari emulators or bsnes. A great example of high level is ultraHLE. The emulator that showed n64 emulation could be done.

I tried NESticle, and it is the closest I have had to working. FCEUltra works when I use it in a small window, but it is hard to see.