My old Win98 box is first edition as well, I think.
I had none of the issues either. P3-500 OC to 550 MHZ V5 5500. Previous box was a P5 166 V3 3000 Win95. Similarly smooth and at that speed level of CPU, rockets were accurate out to their max range.
I suspect maybe it didn't play well with the AMD CPU...and....IMHO, ATI cards (esp. older ones) always gave problems with sims.