1.6.4 laucher

With the 1.6.4 laucher you can not allocate minecraft ram so whenever I use it my pc starts getting insanely hot
I only have about 188 mb of ram allocated and I cant allocate more
I haven't run out of ram, my pc Is new

That minecraft would run better

I saw in f3 mode I had 939 mb of memory for minecraft but only 188 were used

Its not a bug it just a realy annoying problem