1) exactly what query are you using to identify the signal waits (and waits in general)? My guess is something like Glenn Berry's which is since server uptime or last reset, in which case you will be tracking stuff during all your batch operations such as data loads, reindexing, stats updates, checkdb, etc, which could be meaningless for your operational needs.

2) what are other high waits?

3) do you have any affinity settings other than default?

4) are these virtualized servers by any chance?

5) is anyone complaining about poor performance?

6) there are some very significant bug fixes in SP1 through CU6 (current highest build). I strongly recommend you try to upgrade to that.