SafariSyncClient Memory Hog – What's Going On?

All you Mac Wizards out there:

I've recently upgraded to Mountain Lion on my late 2008 13" MacBook. All seems well except something is haywire with Safari. I keep getting the program SafariSyncClient running and consuming enormous blocks of memory. The processor runs hot and the fans go at top speed while nothing happens (and the machine responsiveness slows to a crawl). I've tried deleting the Safari bookmarks.plist and letting it re-sync with iCloud, and it still happens. It consumes a large amount of processor, too. I've got 6 GB in this, and with only Firefox, PathFinder and a couple of other programs running (none very large--altogether maybe 500 MB), and SafariSyncClient is consuming 3.3 GB of RAM (yes, GB!) and there is a 2.25 GB page file! And this is after a restart. This is crazy! Never had this problem before upgrading. Force quit the application and it just happens again, over and over. Rebooting, purging the cache, whatever...still happens.

Next try is to do a clean start with no background apps, but on my iMac I have all the same stuff running, but no issue with SafariSyncClient.

So Frustrating!

I've searched and searched and have found little report of this issue.

Any ideas? Here's a shot from Activity Monitor.

Thanks so much.