trouble with motion rendering on 8 core 26gb of ram

Hey guys,

So I have a projet that is 1280 x 720p I am doing continuous work with hours of footage. Initally i was compositing on my macbookpro i5 8gb of ram and it took 7 hours to render a 1 hr timeline. to remedy the situation, i bought a 8 core 2x 2.4 quad core macpro installed 26 gb of ram and am currently using the 5770 radeon gpu. it say it will take 2 hrs to render which is awesome but........ it always hangs. i check my activity monitor and it uses about 19gb of ram, but when i check the file (rendering to prores 4444 without alpha 1280 x 720p) it only goes up to 3gb and the render status says 35% complete but the timing doesnt change , it doesnt count down or up or nothing. i checked my ram and its all installed correctly so i have no idea what is goin on. when i had my original 6 gb of ram on the 8 core was rendering the same footage it would take 4 hours. sooooo.....i am absolutely confused. anybody having the same issues?