Dreamcast Emulator Any faster ones?

hey, when i try to play almost any game, from the cd or cd image, they slow down a lot during game play. a lot below 60%.

i have a p4 3.06 ghz, 1 gb ram, windows xp, geforce fx5200.

i tried, virtua tennis, super slow
rival schools, slow
capcom vs snk slow

even without sound they still ran below 75%.

but on my dads they work fine, but he has vista and so sound sux.

he has 1.8 gh core 2 duo, 2 gb ram, vista, and the chipset video card.

please tell me i can fix this without having to buy a core 2 duo, and new motherboard.

thank you.

Buy a core 2 duo or wait for the next version to improvement the bugs and the speed. :)