Anyone downloaded and started using 8.4 yet? Its the beta version and supports 64 bit operating systems. Ie can now access more than 4GB of ram if fitted to your machine. 
At last!!!
Am I right in thinking this will increase the CPU performance? Will it actually double it?
Allows your computer to utilise more than 4GB of ram.
For example if your PC has 4 gig of ram then a 32 bit version of ableton can use all 4 gig. If you have 8 gig of ram fitted in your machines a 32 bit version of Ableton would still only be able to use 4 gig. A 64 bit version is able t use all 8 gig or more depending on how many gig your machine is.
More ram utilised would appear to be less CPU intensive i think - therefore the more ram you have the more tracks of audio, midi and VST’s you should be able to run at any one given time.
Well thats my view anyway 
Read this:-
http://www.ableton.com/articles/ableton-live-84-beta-introduces-native-64-bit-support
Oh well, that’s no good for me as I’ve only got 4gb anyway… Desperately need an upgrade!