timed_fragment_cache Slowdown!

Hi,

I've implemented timed_fragment_cache in an app I'm working on. It works
fine, but my entire app has slowed down. Many pages where I use to get
60 req/sec, are now at 15-20 req/sec and the percentage of processing
time spent rendering is now 40-50% higher. Most of these pages use
regular fragment caching; I'm using timed_fragment_cache on one fragment
only. I really need help... any ideas or alternatives to
timed_fragment_cache that don't use memcache?

Thanks!