SSF2's power is mostly drawn from your processor and much less anything else. I can provide a quick bracket for what you can expect for the requirements, my old processor's performance on this game and now my new one.

AMD FX-6300 = low-mid settings 15-25fps, 26-30 fps on lowest
Intel i5 8600k = ultra settings + overkill 30fps

If you're gonna upgrade and don't want to get screwed over simply by the raw processing power this game wants and needs, then you can thank me later. Most modern processors, especially any Ryzen or Coffee Lake can probably run this game at full (and yes this info applies to online mode).

actually if you wanna reduce lag the #1 thing is to look for strong single core performance. the AMD FX-6300 actually is pretty powerful but when you can only use one core + hyperthreading its garbage - most AMD processors rely on using many weak cores.

Avoid if possible
- Anything AMD
- "Y" series intel processors (Y as in yeah this won't run SSF2. IE i7-7Y75)
- "U" series processors before gen 8 (U as in U probably can't run SSF2 well on this. IE i7-8650U)