dude why mikrotik does not release a mk version in 64x? since that way it would be much more capable of managing memory and other resources. Another thing is to use 1 single precessor to calculate routes, this makes the bgp take about 10 to 15 minutes to go up one full. would not have how to use more than 1 core? for this function

There is already a x64 version. Use search and read the whole thread, there is a catch.
viewtopic.php?f=1&t=116621&hilit=x64+mikrotik

There is a non-supported way of getting x64 as previously mentioned however it's negligible if there are actual gains from doing this. If you are looking to run virtual then you should look at CHR as that is x64.

Multi threading is somethign which comes up often on this forum and IIRC it's something to do with the Linux kernel for rOS6 which does not allow this, its rumoured that rOS7 will do this however there is not currently a release date for this.