I was just wondering is cgminer reporting an efficiency of 555% is normal. It is always around there btw, I use stratum.
With Stratum, your efficiency is always going to be extremely high if you're mining on basically any GPU/FPGA. Basically 1 share [diff1] per 30 seconds = 100% efficiency [if I'm remembering correctly], and it scales from there (1 per 15 = 200%, 1 per 10 = 300%). I may be wrong, I can't remember exactly how efficiency was calculated on Stratum, since you basically receive 1 work unit per 30 seconds regardless of your speed. The stat is mostly useless because of that fact.
Yes that's right. It's largely of historical value when the getwork protocol was often the rate limiting step and means less and less with both stratum and variable difficulty.