According to the instructions that come with Qemu 3.04,you must go to the website -
http://www.h7.dion.ne.jp/~qemu-win if you are a Windows user, to start the acceleration if you get a message that it's not working efficiently in a cmd prompt box ? (ie; layered acceleration not working...)
You can improve the speed of this virtual machine by installing Kqemu.
It is available at
http://www.h7.dion.ne.jp/~qemu-win (Section "Accelerators").
Sorry, I hope this isn't totally confusing...As I am a noob to this...