optimize ram usage

[Henrik]

PPSSPP uses some more memory that your monitor apparently can't see, about 48MB more. (32 for the PSP RAM, 16 for the JIT buffer IIRC).

The JIT is really a good example of trading RAM for speed - by caching recompiled PSP code, we save so much time. Same with the texture cache, we use VRAM to cache converted textures. So PPSSPP really does what you're asking for already.