No not really, 98/mamewah sounds about right for that system. Skip dos, your machine doesn't suck that bad.
Well, I dunno. If you have any sound problems, emdkay, with regards to garbled noises, repeating, stuff like that, then DOS will solve that problem. However, you're pretty much limited to Gamelauncher and ArcadeOS for easy-to-use FEs, and only a handful of emus. ZSNES, Magic Engine, and a few others run much nicer under Windows.
I've chosen to foresake the sound problems I'm having (remember my system specs) and use Windows 98 as it will run all the emus I'm wanting to use.
Odonadon