Is my armature too big?

I am modeling (roughly) a human spine. I have created a stack of 28 bones (meshes) with an IK chain of 30 bones (28 bones + 1 null + 1 IK solver). When using Blender 2.36 on a Dell 2.1Ghz, Windows XP platform, there are unexplained pauses of up to 3-4 seconds at random moments when posing this armature.

First, is the chain simply too long? Other than the pauses it poses normally aside from being slower because of the length.

Second, why are the pauses at random moments? A pause at startup might be understandable, as it’s ploughing through the math necessary to deform a stack of twenty-eight bones. Why would a pause occur at other, random, moments? Perhaps I should stay on a Linux platform?

Finally, to avoid all this confusion should I reduce my spine model into three sections (cervical, thoracic, and lumbar) to reduce CPU demand and speed posing?

Thanks, Bob

The easiest way to find the answers to your questions is to model a spine with less bones and see how it responds. Is it really neccessary to have so many bones for te spine?

huge IK chains will slow down your scene. use less bones if possible.

The anal-attentive part of me wants to be true to a human skeleton but the pragmatic part simply wants a flexible spine. I will be modeling a human performing yoga postures, and a limber model is necessary.