From Kokua Wiki
We currently offer two builds of Imprudence builds for Windows: normal, and SSE2 optimized. This page is meant to help you find out which one is right for your computer.
What is the difference?
The normal build is compiled to be compatible with the widest variety of computers. The SSE2 optimized build runs somewhat faster than the normal build, but only works on computers with a processor (CPU) that supports SSE2. If you try to run the SSE2 optimized build on a computer that does not support SSE2, Imprudence will most likely crash or not run at all.
Which should I use?
That depends on whether your processor supports SSE2.
If your processor does not support SSE2, you must use the normal build. The SSE2 build will not work for you.
If your processor does support SSE2, we recommend using the SSE2 optimized build to get the best performance. If you experience any problems with the SSE2 opitimized build, you should use the normal build instead.
According to Wikipedia's SSE2 page, the following processor types support SSE2:
- AMD K8-based CPUs (Athlon 64, Sempron 64, Turion 64, etc)
- AMD Phenom CPUs
- Intel NetBurst-based CPUs (Pentium 4, Xeon, Celeron, Celeron D, etc)
- Intel Pentium M and Celeron M
- Intel Core-based CPUs (Core Duo, Core Solo, etc)
- Intel Core 2-based CPUs (Core 2 Duo, Core 2 Quad, etc)
- Intel Core i7
- Intel Atom
- Transmeta Efficeon
- VIA C7
- VIA Nano
If you're not sure what processor type your computer has, you can find that information in the following locations, depending on your version of Windows:
- Windows XP: Right click on "My Computer", then select "Properties" from the menu, then switch to the "General" tab.
- Windows Vista: Open the "Start" menu, click on "Control Panel", then "System and Maintenance", then "System". 
- Windows 7: Open the "Start" menu, right click on "Computer", then select "Properties" from the menu. 
- Linux: Open a terminal window, type (without the quotes) 'more /proc/cpuinfo | grep -i sse2' and if you get no result, your cpu is not SSE2 compatible
There is also free tool out there to check if you CPU supports SSE2. You can find it here: []