just brew it! wrote:
but since I normally don't do a lot of stuff natively in OS X, I can allocate a large chunk of the RAM to the VM
The VM is only using that RAM (at all) while it's open though. So the amount of RAM you need is highly subjective not only to your task needs (inside and outside of the VM), but also depends on your usage habits. Also, the amount of RAM you "allowcate" to a VM is an "up to" amount. If the VM is using less than that, the primary OS still has access to the remainder. A lot of time, RAM allocation is based on the probability the both the primary OS and the VM(s) are using x amount of RAM concurrently.
For instance, if you're like JBI working in a Linux VM because your company only provides Macs, then his Mac OS is simply a host to his Linux VM. Assuming that he's doing little->nothing on the Mac OS, he can allocate a majority of the system RAM to the Linux VM (as stated)
Second example. You work on both the primary OS and the VM with RAM-heavy workloads, but rarely at the same time. If your workflow has you in EITHER the VM or the primary OS for longer chunks of time, you could easily sidestep the RAM sharing limitations by simply closing the VM workloads when you're ramping up workload on the primary OS, and/or closing down your RAM-heavy workloads on the primary OS when you need to go back over to the VM. Sure, this requires "custodial" maintenance of not running RAM-heavy workloads concurrently in both environments, but generally your work flow would avoid this issue for the most part.
Third example, you're heavily number crunching on both the VM and the primary OS at the same time. In this case, yes, you need enough RAM to run both at the same time (keep in mind, you're also sharing all other hardware resources also, so the bottleneck may not even be in RAM amount, just that RAM is the easiest bottleneck to remove).
I personally don't use/need VMs for personal use, and I'd wager that a LARGE majority of people don't either. Obviously a place like TR is going to have a higher % of readers using VMs simply because of their techie background.
Other "cool" things you can do when you have more RAM than you need........a RAM drive
Main: i5-3570K, ASRock Z77 Pro4-M, MSI RX480 8G, 500GB Crucial BX100, 2 TB Samsung EcoGreen F4, 16GB 1600MHz G.Skill @1.25V, EVGA 550-G2, Silverstone PS07B
HTPC: A8-5600K, MSI FM2-A75IA-E53, 4TB Seagate SSHD, 8GB 1866MHz G.Skill, Crosley D-25 Case Mod