If you find emulation very slow please try the following steps:

• Scan for any adware / spyware and remove
• Use up-to-date drivers (soundcard, graphics card drivers etc)
• Defragment hard disk
• Disable any unnecessary background software
• Try disabling filters if you use WinUAE. - Filters such as 'Scale2x' look nice but can slow things down if you have a low spec PC (i.e < 1.5 Ghz CPU). If you do use filters make sure, under 'Host > Display' settings, you use 'Normal' line mode and tick the 'Lo-res' box to get more speed.