[SkizzoTrick]

Hello,
i have a pretty stupid question but i want to find the answer.
What is samp.dll doing? What is the difference between samp.dll and samp_a.dll?

[Pizzy]

I don't even have a samp_a.dll

the samp.dll is most likely the code that is injected into the GTA_SA process, to modify it.

[Mauzen]

samp_a.dll was part of some older versions. It isnt required by todays versions anymore, probably it was just renamed to samp.dll.
You can remove it or just keep it in your gta folder, doesnt matter.