I've heard from one tech guy that Windows 7 should be installed only with original (integrated) interface language and all the LIPs and MUIs can affect, sometimes drastically, Os's stability and performance. I think otherwise but can`t find any proofs. A couple of years ago I also read on some forum that the most stable version of Windows regarding interface language is English. As for me, I never had any issues installing language packs (mostly on English systems), but I want to understand this better - should I download only original ISOs or use English version + MUI or LIP? Any help and links will be appreciated.