RAMdisk in OSX revisited

RAM Disk is virtual memory, i.e., you hard drive is being used as "RAM memory". Your Mac's access to virtual memory is much slower than actual RAM memory. OS X already does this automatically when necessary, so there's no need to create a RAM disk.

 Cheers, Tom 😉

Firstly, watch the language. Secondly, read the following:

About OS X Memory Management and Usage

Reading system memory usage in Activity Monitor
Memory Management in Mac OS X
Performance Guidelines- Memory Management in Mac OS X
A detailed look at memory usage in OS X

Understanding top output in the Terminal

The amount of available RAM for applications is the sum of Free RAM and Inactive RAM. This will change as applications are opened and closed or change from active to inactive status. The Swap figure represents an estimate of the total amount of swap space required for VM if used, but does not necessarily indicate the actual font size of the existing swap file. If you are really in need of more RAM that would be indicated by how frequently the system uses VM. If you open the Terminal and run the top command at the prompt you will find information reported on Pageins () and Pageouts (). Pageouts () is the important figure. If the value in the parentheses is 0 (zero) then OS X is not making instantaneous use of VM which means you have adequate physical RAM for the system with the applications you have loaded. If the figure in parentheses is running positive and your hard drive is constantly being used (thrashing) then you need more physical RAM.

Thirdly, to what virtual memory are you referring? If the Vmem column in Activity Monitor, then that number is meaningless to you and has nothing to do with the swap file. Whether the contents of your ram disk are written to the hard drive is a function of how the ram disk handles the content upon shutdown/restart.

Tom,

I think he's referring to creating a pseudo-drive in physical RAM - hence called RAM disk. He's not referring to disk-based virtual memory.

Because the program itself has assigned some virtual memory allotment as do all the running programs. This has nothing to do with what the Ram Disk program does nor does it mean that anything you put in the Ram Disk is not in physical memory. There is no swapping going on with the program. The program works perfectly well, and you are focusing on something that is meaningless to you.

And, the bigger your RAM Disk, the more likely the data will be written to VM before it ever gets to the RAM Disk.