Anyone else seeing this kind of reoccurring drop in hashing, I suspect it's got something to do with cgminer restarts or the like? I have other miners running so the graph doesn't hit zero but the new KNC miner does completely go offline for long enough that the graph picks it up....
I see that kind of thing on Eligius when someone is trying to DDOS the pool. It's been happening off and on quite a bit lately.