LMS hogs 100% cpu

Frequently, the web interface on LMS becomes very slow, though still functions, and the squeezeboxes are also slow and unresponsive to IR commands. This happens even when there is no music playing and no scanning is going on.
Looking at the CPU useage, squeezeboxserver is hogging 98-100% of one of the cpus.

After a while, LMS reverts to normal and uses c2% of cpu time when idle.

I’ve looked in the server log files (with all the logging options at the default “error” setting).
Ive tried setting various logging options to “debug” which produces copious log data, but I can’t see anything that would indicate a cpu running flat out

Has anyone else experienced anything like this?
Any suggestions on how to diagnose what the problem might be?

I'm a long time user of Squeezeserver etc and haven't experienced anything like this before. Nor can I think of any relevant changes to my system which might have caused this.

Thanks for your help

I’m running LMS 7.7.2 r33893, Ubuntu 12.04.1 on an Acer Revo 3160 Intel Atom 330 (4 x 1.6gHz core), 1.5Gb Ram, 2Tb external drive
3x SB3, 1x SB2, 1x Transporter (mostly wired)
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