just use git directly then without a gui server? or hell if you need a gui use upsource, that needs 8 gb ram however it is down you still could use everything else.
https://www.jetbrains.com/upsource/ (just repository browsing and code review not hosting, for hosting you need to create your bare repos yourself which is not hard)
Especially these days where everything is done on the client and the server only has to run a simple API!