Comment Re:Weeding Out (Score 1) 270
If you have more threads than cores, obviously it slows down, in any language.
If you have 5000 'working' (not sleeping) threads on a single core, obviously they have to share the processing power, obviously every thread can only run with 1/5000ths of the cores capabilities (much lower even due to context switches).
That is a no brainer and has nothing to do with the language.
But good luck running 5k threads with C or C++ then
As others already suggested: try Erlang