It will save disk space on drive C: plus it's pretty pointless to have when you have 4GB or more RAM.
No. It's not. the Page file is
required in order for the Virtual Memory Manager to function properly. Without a pagefile, the VMM can only manage memory in larger 64K chunks (pages), as opposed to the 4K pages it can deal with when there is a pagefile. This is to prevent memory fragmentation, on account of the fact that without a pagefile no swapping can occur, in which case when a program allocates a piece of memory that memory is there for good (without a pagefile) until it's deallocated or the program terminates, as opposed to that memory being fully swappable.
The net effect of not using a pagefile is that you get a limited uptime as a result of the fragmentation that will occur eventually as well as lower memory performance overall from the VMM.
Re: the original topic of RAM drives.
The last time they have had any use was with DOS, since you could convert extended memory into extra disk space when you were running programs that would otherwise only use conventional memory. Additionally, hard drives were
very slow back in those days (todays hard drives aren't much slower then memory was then). Usually, the user would create a RAM drive (using DOS's VDISK.SYS or RAMDRIVE.SYS) that used extended memory or conventional memory or whatever, copy appropriate program files to that new drive, run the program from there, and then copy any needed documents or anything that needed to be persistent back to the hard drive, since everything on the RAM drive would be gone after a reboot or when you shut off the machine.
There are some implications that putting a pagefile on a RAM drive would increase performance. This is blatantly false.
The pagefile is there ONLY to hold data that is by definition "stale" if you haven't used photoshop in a while but it's still running, all the non-shared data pages are paged out to disk. "So" you say, "now that paging and paging out is faster!" And you would have me there. But by making a RAM drive, you are reducing the amount of total available memory (bear in mind that despite what some people have said in this thread, you cannot create a ramdisk outside the ~3.5GB barrier of most consumer windows systems). Guess what you are doing by reducing the total amount of available memory? making data go stale faster. Now memory fills up quicker and therefore data will be paged out more often. Note that data is only paged out when necessary, so if you have 8GB of RAM, data will only be paged to disk when a program either purposely forced it to be paged to disk (for whatever reason) or when physical memory is low, or certain functions are called.
So, even though you managed to make page operations extremely fast by using 4GB of your 8GB of RAM for a RAM drive and storing the pagefile there, you've defeated the purpose. All that is happening when you page now is that data is being copied from one area of memory to another; whereas if you had simply used a disk-based pagefile, you would be paging less and that 4GB of memory would be used as memory itself rather then some psuedo-copy location. Using a pagefile on a RAM drive defeats the entire purpose of the Virtual Memory scheme itself, and causes any number of the assumptions used in any Virtual Memory manager to become false; with a Virtual Memory manager (which essentially decides what get's paged to the pagefile and when) the assumption is that the pagefile access time is slower then memory, and that both can be accessed concurrently. When you create a pagefile in a RAMdrive, you are invalidating this assumption, which can only lead to less-then ideal logic and therefore less-than-perfect memory management. This combined with the fact that you have reduced the total memory lead to reduced performance all around.
Now, putting a pagefile on a SSD, on the other hand, is a different story. a SSD drive is still slower then System Memory, and can still be accessed concurrent with system RAM. It makes a perfect place to put a pagefile; however, bear in mind that the performance increase by putting a pagefile on an SSD is not as great as the increase from installing the OS files and programs on an SSD.
