Optimizing your Mac: SSD for Fast Virtual Memory
Virtual memory is “fake” memory: when the Mac runs out of real (physical) memory, the stuff actually installed in your Mac, Mac OS X fakes it by swapping “pages” of memory to and from disk.
Many Macs cannot install more than 4GB, 6GB or 8GB of memory, a good reason to go with the Mac Pro, which can accept 16GB, 24GB, 32GB or 64GB (and perhaps more with future models). The newest iMacs do take 16GB, but zero options for faster or more drives.
Solid State drives to the rescue
Assuming you’ve maxed-out the physical memory your Mac can hold ( highest density modules fill all available memory slots), but your programs still need more memory, all is not lost.
The right solid state drive (SSD) will provide a huge performance increase with virtual memory as compared to a hard drive, because there is no seek time, latency is all but zero, and the transfer rate is about 2.5X faster. All told, performance can be 10X faster than with a hard drive!
As of May 2010, the only drive we recommend for this purpose is the OWC Mercury Extreme, because it not only starts with ultra-high performance, it maintains that high performance under duress.