no$gba using up all my processor speed , why ?

Ive got an AMD 3200 with 512 mg ram, windows xp.
first of all i got no$gba and it works great , runs roms that no one else will.
but after about 10 min my computers processor overheat warning went off, i was confused untill i checked task manager and it told me that no$gba was using 98% of my processors speed.
why does it do this, (and yes this was the only program running).
very confused ??

because emulation is highly CPU intensive.

any way to slow it down so it dont overheat my computer ??

no.