I've had a few cases recently that have brought this issue to the fore.
It's amazing how many people think that the answer to all performance issues is to simply throw more cpu at the problem.
Let's work through this thought (and this holds true for other queuing type locks too).
What does this tell you about what is likely to happen if you add more cpus into the mix?
It's relatively obvious now, isn't it.
The obvious consequence being that adding more cpus can actually have the effect of making the problem worse.