SSDs based on the right gate type and capacitors are faster, albeit not by much. This has been proven countless times, these disks don't run circles around 10k RPM Raptors yet they cost 4-5x as much per GB. Now with their prices coming down, they're looking better, but most of them are still far better on paper than in pudding. I know, I've bought enough and benched enough to reject them. Also, the DRAM chips used in SSDs are not the same as those used on memory modules. They don't have the access time or the refresh rate.
Which is why I use a 64bit OS. =)
32bit OSs can only address 4GB of memory, and that includes more than just the system's RAM modules. That's why I specified "For someone with 2GB or less RAM, no open RAM slots, running 32bit Vista, and an available USB2 port or header, it's a fantastic option to increase performance." For someone with a 64bit OS and empty RAM slots, ReadyBoost may as well be called a Vista Boot Drive, cuz that's all it's worth.
The real world gains are negligible at best and an absolute waste of money at worst. Again, I've done. Most drives not labeled as ReadyBoost-compatible not only give no performance improvement but tend to bog the system down because CPU cycles are wasted managing their storage space as program-addressable memory. But like I said, when running a slower computer with <=2GB RAM, it helps enough to be worth the small investment. My quad with 8GB saw zero real-world improvement from a 4GB ReadyBoost drive in everything except for Vista load times. With a generic crapstick, there was zero difference no matter what I threw at it, from gaming to CAD apps.
All good info, thanks for contributing.