Logic 8 not using all RAM

Question

I'm running Logic 8 on a MacPro 8-core with 13 GB of RAM, but Logic always crashes once it's used about 6.5 GB of memory. I'm trying to run a lot of sample libraries and plugins at once (Vienna Instruments, EWQLSO with Kontakt2, Stylus, EXS24 instruments, etc.), but it reaches a limit and crashes, telling me "could not allocate enough memory" and other memory messages like that. How can I get Logic to use the rest of my RAM that's just sitting there?

Answer 1

Ok here's your first problem... 13 gigs of ram. If you read and pay attention to Apple's info, you'll see that they highly recommend you pair up the RAM chips and use the same ones, otherwise you're using 64bit memory addressing as opposed to 128, which of course means processing things faster. Look at your RAM configuration and look at which ones are not paired up, I'm thinking you have a pair of 512MB DIMMS in there which should be taken out, yes you'll lose a gig, big deal, you'll gain speed.
Second, Logic can't use more than 4 gigs of RAM. It's not a 64bit application. 64bit as it's compiled, I am not talking about the audio engine. The fact that it reaches 6.5GB is because EXS24 has its way of starting up more processes which can use 4gigs of ram Each. Logic itself is not using the 4 gigs.
The reason you crash is because one of the plugins you're using is not written properly to let Logic know that it's running out of RAM, and hence Logic tried to take up more and crashes because it can't address more than 4gigs of ram, and when it does... boom. As an example of that, BFD 1.5 used to be like that, until FX rewrote their code to work properly, and now when BFD2 tries to get above what Logic is capable of, it stops loading samples and throws up a little popup telling you you're running out of memory.
Your problem is not logic, it's one of those plugins which is not written properly.
R