One thing you can do is use the purge function in K2 to free up some resources by getting rid of samples in memory that are no longer needed.
Yeah that's a great feature... I use it all the time. I did however need to purchase a faster hard drive to work with K2. Probably because of all the 24-bit samples I've accumulated. It more robust compared to v1.53 and CPU resources seem to be tapped a bit more. On board Giga conversions are good for simple things... CDXtract would be my first choice for more complicated libraries but don't expect miracles. All in all, I'm happy with it.
I'm also considering jumping ship from Halion to Kontakt. - I like the purge memory feature in Kontakt, and the ability to load a program (for editing purposes for example) without pre-loading all the samples first. (A feature Halion doesn't have). - However, in playing with the Kontakt 2 demo with TBO, I noticed a few pops and clicks when using Xavier's True Resonance behaviour. - Either I have not got my settings correct, or it's not as efficient as Halion - does Kontakt have a pre-load setting, to adjust how much of the sample is loaded into RAM, like Halion does?