Feel free to compile it and replace your object file with it to test its benefit.
sorry, but how am i doing this?

also: can i compile the sse stuff without installing yasm on the PC?
(i dont have root access to the PC, i would like to run cgminer on)
for curl i used "./configure --with-libcurl=/home/.../myCompiledCurl" but ./configure is missing a similar option for yasm.

Actually, this was decompiled for YASM. In which case, you copy this text into a simple text editor, save it as cgminer-sha256_sse4_amd64.asm in your working linux directory and then, with YASM installed, simply type yasm cgminer-sha256_sse4_amd64.asm. You can simply drag and drop the asm file from a folder view into the terminal window to make it easier than typing the entire file name. But this increased my hash speed from about 14.7 up to around 16 to make it on-par with ufasoft in Windows.