So if I ran 32bit photoshop and 32bit Lightroom as same time [just an example], photoshop will be limited to 4gb [or less], but will Lightroom will be sharing the same lower 4gb as PS or it could use the other 4gb [granted pc have 8gb or more? The latter. Each process can use 4GB, if the registry key is proper and you're running a 64-bit OS. Each process, more importantly, can request from the OS' process scheduler a block of RAM for its exclusive use. This way your multitasking is much enhanced. Sorry, but honestly [Sarcasm is off] how is it relevant ? Any company serious about their VMs will run it on real server hardware and bare-metal installed OS ESX or Hyper-V, not on top of Windows Desktop :) I try to focus on either consumer or small business users, since most people that would want to know about this kind of information fall into one of these two categories. I doubt a network engineer or information officer for a large company would come here looking for advice on their company's infrastructure, but for the casual user or small business owner it could be useful info. :)