What exactly are you proving with the looptest? It was already pointed out that mIRC is single threaded and does not in any way benefit from multi-core CPUs. mIRC probably won't be multi-threaded in your lifetime, so the feature you described probably won't happen, but, but if you're really requesting multi-core support, please start a new thread-- you're just confusing this discussion by posting it here.
Secondly, is this really the test you ran to prove that blowfish isn't usable on 7.x? Please tell me you've done something more comprehensive than time an empty loop.