It’s quite bad with large amounts of audio in the pool. Some time ago there was a thread about this because we were one of the companies to have complete work stoppages due to the problem. Believe it or not the issue is waveform display - Nuendo stores high resolution waveform display data in memory and there’s no way to free that up. Any audio in your pool chews up quite a bit of memory for this waveform display.
We lost two seats to ProTools just for that reason - there was no way to load a multi-hour large session into their laptops for content cuts which is the first and most basic thing they do. They had 4GB of memory and couldn’t comprehend why they couldn’t load a project. Our Macs do better because the apps can use a larger amount of memory before they run out but we still can’t do many of our programs running in 32bit or with under 8GB of memory.
Steinberg doesn’t think this is an issue, and if I remember correctly there was a response that, in essence, said that folks needed new hardware and to get over it (in a polite way of course). Which of course wasn’t possible on the Mac at the time as there was no 64bit Nuendo. Pretty silly and still a source of problems for some of our users.