playing Pokemon Diamond/Pearl on PC?

http://desmume.org/

Its the best aswell as fastest ds emu available. the link is to official website for the emu.

To get a HUGE speedup, go to emulation settings > enable the JIT recompilier. Leave block size at 100 unless there are problems loading the game or any major bugs in the emulation of the game. Then you should try lowering the number to something like 10 or something.

If it still wont work with it, either bring block size to 1-2 or turn off the recompilier.

(the higher the block size, the bigger the boost in speed, but less compatibility with games. Most work with it though)

You can enhance visuals (since the DS native resolution is like 320x240, and when stretch to computer size monitors, it gets very pixelated), by going to view > magnification filter.

BUT this does come at a high cpu cost, and may cause slow downs on weaker cpus.

Try both openGL 3.2 and softrasterizer. Use which ever gives you more speed.

You can increase speed further by turning on frame skip. Its best to use at 1-3, but you can use 4-6 if you really need it, but skipping that many frames can cause some choppiness. any more is unplayable)

Most the rest of the settings leave defaults. (other then input kind bindings and hotkey binds).

using above settings, it should be playable at full speed on like a 1.5-2.0ghz core 2 dou.