I just started adding roms and playing around with pimame. I've tried about 30 different games so far and, for the most part no problems. 1942, donkey kong, galaga, work fine with my keyboard. A few run really slow (star wars arcade, spy hunter, street fighter 2) and I'm assuming that's because my raspberry pi only has a 512mb processor. Would stacking something else on it help? Also, some roms I upload don't show up, the ones that do are only in advmame. mame4all and consoles show nothing for roms, even though I've uploaded some playstation, nes, and neo geo games just to see.
Eventually, I would like to build a cabinet but, for now just trying to get the basics down. There's a couple of joysticks I'm looking at, wondering if anyone has any experience with these or can recommend better for just starting out.

http://www.amazon.com/Universal-Arcade-Fighting-Joystick-Playstation-3/dp/B0015PHMFU/ref=pd_rhf_dp_s_t_2

http://www.amazon.com/BestDealUSA-Laptop-Arcade-Durable-Joystick/dp/B00973TPHA/ref=pd_rhf_dp_s_t_3

thanks in advance for any help.