What are the difference between lame3.90.2-ICL and lame3.90.2-MSVC?
3.90.2-ICL / 3.90.2-MSVC / 3.90.3 / 3.92 which one is better?

Thanks!

3.90.3 is the recommended LAME version.

"ICL" stands for "Intel C++ Compiler" and "MSVC" stands for "Microsoft Visual C++ Compiler".
IIRC, the ICL compiles should be faster.

IIRRC the difference between the two 3.90.2 is compilers. The reason they are both provided is one or the other runs better, faster or just manages to run depending on your machine. Also ICL was used to tune the alt presets. Since you have different bit output depending on your compiler, many purists believe you should use this compiler. 3.92 can be forgone. Now better? Test them and see.

LAME 3.96 has already been released...are you aware of that? So I don't quite understand why you are only asking whether you should use LAME 3.90 or LAME 3.92. I personally would recommend LAME 3.96 to you

ICL is faster for Intel processors. MSVC 6 build are also optimised for Intel cpu but less. If you own an AMD, you should go for a custom MinGW compile, for example a build with "-O2 -march=athlon-tbird -m3dnow" gives me a 50 % speed boost over ICL (for lame 3.96).
Still I had heard on hydrogenaudio about tiny differences in sizes of mp3 files produced with different compiles because of some rounding errors with ICL, but it was not ABXable and the size difference was really negligible.
So to sum up it's quite all about speed.

thanks a lot!! everybody!