Хм, сама MS для Win7, как и прочие, рекомендует размещать swap именно на SSD. http://blogs.msdn.com/b/e7/archive/2009/05/05/support-and-q-a-for-solid-state-drives-and.aspx
Should the pagefile be placed on SSDs?
Yes. Most pagefile operations are small random reads or larger sequential writes, both of which are types of operations that SSDs handle well.
Там его и держу при наличии второго HDD, в отличие от всяких TEMP и т.п.