I can't speak to the actual problem, but in general laptops have much slower performance than desktops. They just can't move data around as fast...bus speed, memory speed, disk speed. They are optimized for form factor and power consumption rather than performance.
Using Cubase 4.5.2 on my Macbook Pro 2.2Ghz with 4 gig ram i loaded up 7 channels each with 8 Nitro plugins as inserts and it played ok. So thats 56 instances without any problems. Was only using the internal speakers as i didnt have time to fire up the whole studio...
Does nitro run off of impulses at all or is it all algorithmic? I just read on a forum somewhere comparing distortions that it was an impulse in nitro so that could explain the high cpu...but...it's just something i read and have not followed up on. Either way, i'm curious if anyone knows more.
I use it like SSL VHD type things, adding size and girth to tracks. The waveshaper is very musical.
It has a great bit crusher and the stereo spread it also very nice. I have even used that on a main mix before very subtly!
I have used it to do a psuedo-transformer like distortion saturation that is LF and level specific.
Try the waveshaper set to low order harmonics with high saturation. Instead of applying it over full-bandwidth, apply it in parallel to L.F only (filter before it @ 500Hz or so), blend back in and perhaps roll some extreme top off if not smooth enough. You can set the saturation to be modulated by an envelope follower to give you level or input based saturation drive...so it is a little program dependant. The only thing to watch is the phase shift from parallel filtering. Nice thing is: you can do all this in one plugin! You can have it fatten tracks or use it on a kick drum sample to have the envelope follower open the top end of a filter at high input levels to take a sample with one dynamic and give it some tonal variation.
I have used the envelope follower to create some interesting effects, also using it as a MIDI gate. It can sense midi input and you can use it modulate parameters like the atten or cutoff. So you can have it chop pads up to the feel of a hihat pattern etc. I like sliced effects. The nice thing is you can do that, but then set up a little delay with some feedback to fill the gaps, cool remix tool.
I just managed to get around 20-24 Nitro plugs running now with an increased buffer size on internal speakers. Version 1.0.6 says it is Altivec optimised but I thought that was an old mac thing?