So I went through A+ 4 or 5 years back (when the exam was 601 and 602). The book covered Windows XP (and referred to Vista a bit). The author said that the virtual memory should be roughly 1.5 times the amount of physical memory installed in the machine. Better yet, to set the minimum and maximum virtual memory to the same size to avoid fragmentation.
It's now 2012 and we have Windows 7. I just built a computer (from left over parts + new ones) and it has the most memory I've had in any machine (8 GB DDR3). Would you guys still recommend 1.5 times 8 GB or different settings? I thought that disabling virtual memory altogether would be ideal (because why run anything in virtual memory if I have lots of physical memory). I did my research and found a lot of people said that it's not the case (unless that's false). I figure that the least amount of virtual memory used (while the most physical memory used) would result in the best performance (because clearly physical memory is much faster than virtual memory).
Memory management in Windows 7 is much better so fewer people actually need to adjust the Virtual memory settings. However, if you want to change them it wont hurt anything.
The biggest advantage in setting a fixed size for the virtual memory page file was to keep windows from using up a huge chunk of the drive for virtual memory. On a 40GB drive with windows XP the system could eat up a tenth of your drive just for virtual memory.
For example, with WinXP and 1 GB memory the system could potentially use 3-4 GB the disk space for vitual memory. On a 40GB drive that's up to 10% of the drive space leaving only 36 GB for the OS and data. With Win XP using around 4-5 GB of that you could run out of disk space pretty quick.
With Win 7 and 8GB memory the system might use 24-32 GB of space (assuming the same ratio's). On a 320 GB drive you still have well over 250 GB left. Even with win 7 using 20GB of that there's still an awful lot of space left.
The 1.5 rule is very old, and I actually ignored it. The reason is that up to (and including) XP, the OS seemed to favor cache as opposed to background apps. I think ever since 64MB RAM in 95, I always disabled paging file. And now I'm using 8GB in Windows. I even limited my laptop to use only 4GB out of 8, but that is due to hibernation file, rather than page file.
PS: just in case you are wondering, my laptop came with 1 4GB stick, and I bought one more for dual-channel...so that combined with hibernate file made me decide to limit to 4GB.
It depends on how many programs you normally run at once. I've been running win7 x64 with 8 gig of ram, but have the page file set to half that and have no problems. Whatever size you pick, just set the min and max size the same in order to avoid fragmentation.
Also, some programs refuse to run without a page file, but those are becoming fewer these days.
Run what you would consider a normal days app load, take a look at pagefile usage in Task Managers Performance and use that as a guide to set a static pagefile size and add say 500MB just in case you get a usage spike.