I can run Kontakt in 64 bit SPlat without any errors, memory warnings or crashes when using C. Bechstein Pianos.
 
When I try to use them in 32 bit SPlat I get: "Looks like there is no memory left. I'm afraid we are about to crash, soldier." when there's 8.8GBs out of 16 available.
 
This is followed by a fatal error in Sonar, VCRUNTIME140.dll. and it crashes.
 
Maybe C. Bechstein Pianos don't run in 32 bit.

Just curious. Why oh why would you run 32bit SPlat when you have 64bit SPlat available?
 

32bit apps have a 4gb memory usage limit.
So an instance of 32bit Kontakt can't handle large libraries or combination of libraries if that usage exceeds 4GB.
Don't recall if when running SPlat 32 bit if everything has to run with in same 4GB memory space or if each VST has it's own 4gig limit.
 
 
 

That makes sense and sounds like what's going on here. It would be nice if Bechstein mentioned this or list actual system requirements to that level, but they don't. All I can find for requirements are Kt 5.6 and "a Mac or PC not older than 4 or 5 years old."
 
BTW, their screenshots show Kt 5.5 but it will not work with it.

It's actually worse than that; 32-bit Kontakt can only allocate a maximum of (slightly under) 2 GB for all instruments.
 
My initial motivation for moving to 64 bits in the first place: Orange Tree Samples' Rickenbacker bass required more than 2 GB. I was able to kludge it by creating an .nki with reduced round-robins and no noise samples, which brought it just under the 2 GB max, but then I couldn't add any more Kontakt instruments. That's when I knew I had no choice but to break up with XP for good.
 
And yes, I agree that library developers should list memory requirements in their technical descriptions. You can tell very little from the library size alone.

I'm new to the NI game and was pretty happy before, never wanting to venture into this "wonderful" world. Then I found a sample set that required Kontakt and have been chasing my tail & wallet ever since. Some doors are best left unopened!

Yes padawan, a powerful tool the NI Kontact is.
Many who seek to master it often burn hole through wallet, repeatedly.