Basics

[epixoip]

what is the main difference between oclHashcat-plus and lite ? when exactly would i choose lite instead of plus ?

plus supports cracking multiple hashes & multiple attack modes. lite supports cracking only a single hash, and only supports brute force. because lite is optimized for single hash brute force, it is much, much faster than plus. so quite obviously, you would use lite when you need to brute force a single hash.

it seems that hashcat only uses CPU power, why would i ever use this old method ?

straight wordlist attacks are faster & more efficient on cpu. cpu version also supports cracking passwords that are longer than 15 characters (although the next version of plus will as well). the cpu version also has a table attack engine. the cpu version is also great for developing and testing mangling rules. it also supports more algorithms than plus.

is there any significant speed difference between a windows8 system and lets say the same hardware powered by ubuntu ?

no.

sometimes i stumble over "Forceware", isnt that just an old term for nvidia drivers?

yes.

one last note: you seem to care an awful lot about performance. you should not use an nvidia gpu if performance is so important to you.