Is using a Virtual PC on a RAM DISK super fast? (putting the .vhd file in a RAM DISK)

Question

I wonder how or if any one tried to create a RAM DISK, and then put the 2GB (or sometimes 1.2GB) .vhd file into it, and then run the virtual PC using this image.

It should be running super fast, as the hard disk is now simulated by RAM... I never tried but saw that there is tmpfs on Linux. So with VirtualBox, it should be doable... How about on Windows or on a Mac, anybody tried before and saw how fast it is?

Answer 1

harddisk speed is the biggest bottleneck nowadays, there are other bottleneck also (e.g. drivers delay, OS architecture design for mechanical drive etc).

Answer 2

It's debatable.

Performance will indeed increase considerably. But if you have enough RAM to create a RAM Disk capable of storing a whole image, know that both VirtualBox, VMWare and VirtualPC are capable of caching your images as data is accessed. So while the RAM Disk doesn't necessarily become redundant, its performance increase over a cacheable image will not be that great.

It's also a risk. A power outage or any other situation where your PC is accidentally turned off will destroy you image (or any changes you made to it since you last load it).

Finally, it will make starting up and closing down the VM session slower as the whole image needs to be read from disk into memory and later saved back to disk.