Thanks for all the helpful info. What size do you recommend for a an SRT SSD? Is there a limit to the SSD drive capacity you can use for SRT?
Size depends on your budget, of course. I got a 30GB Corsair last year, and that's working fine for me, although something a little bigger would be able to hold more in the cache. There is a limit of 64GB; anything beyond that would be split into a separate volume and not used for SRT.
I imagine it would make games load faster on consecutive launch in which case I am very tempted to try it since I do not want to invest in a 400+GB SSD.
Yep, that was exactly my scenario. And that's exactly how it works: After you launch something a couple of times, it caches it into the SSD, and loads it from there. In an ideal world, I'd have an unlimited pile of cash and just get a giant SSD, but unfortunately I'm not there yet!
Do all z77s and z87s come with SRT or just the higher end models?
It's a function of the chipset from Intel, so should work with any motherboard that uses it.
For Sandy Bridge, it's supported only in Z68 chipsets.
For Ivy Bridge, it's in Q77, H77, and Z77.
For Haswell, it's in Q87, H87, and Z87.
Hope that helps!