[citation][nom]smfrazz[/nom]What couldn't we just use a very fast SD or CF card as the OS boot drive? wouldn't that at least provide much faster access to the OS and cache files? Amy I missing something here? If that works then under the same idea, couldn't one use those same fast SD or CF cards for installation of games? Plug in your card of COD - World at War and your off and running.[/citation]
Three words. Interface, size, longevity. I think it's self explanatory.
The interface of these cards isn't fast enough. SSDs are designed in a way that allows more simultaneous access to parts of the flash at once, which means you have to have a lot of bandwidth which only Sata currently provides (there are other interfaces too, but SATA is used currently for HDDs). Furthermore, SSDs have better wear-leveling algorithms, flash cards do not. This makes them better suited for long term storage and repeated use. Flash cards are only cheap because they lack the need for a good, fast controller that has a wide bus and can sort out information quickly to various sectors. This is where size comes in too. SD and CF cards are designed to be portable and small, not particularly fast. They are only intended for use as storage, so they are slow. Fast by older standards, plenty fast for basic small storage too, but if you've ever copied songs to an MP3 player you know that moving massive files or installing an OS would take awhile. SSDs are also better magnetically shielded, as they are designed to be put right next to electronics. I wouldn't put an SD card with valuable information on it too close to my speakers which contain magnets, but my Raptor X hard drive spins right next to my speaker inside my case on my office table just fine for years.