there is no proof that re-pasting affected any of this, and I assume that this is just after a few hours. Some units have a habit of starting bright (at >470), then spontaneously dipping back to 440GH or even lower. It is also possible that OP had great units to begin with.
http://i62.tinypic.com/2wpm9oz.jpg
there is the first four S3's first screens i took ..
what i think the problem is the stock thermal paste ..
two of the S1's in the above pic are under performing ..
those two were unable to be overclocked ..
both of those have same symptom thermal grease leaking ..
i think the under performance is the stock thermal paste touching the pins ..
maybe the stock thermal paste is capacitive ..
which is same reason i think no one sees improvements using AS5 ..
i will be opening those two S1's and swap the paste and test ..
I am thinking of ordering either Arctic MX-4 or GC-extreme to solve this puzzle once and for all. I have a machine that stubbornly performs at 428Gh at 212.5 and worse on higher mhz. I already applied AS5 very carefully (only on chips) with no effect (positive and negative). I will order one of the pastes above and try again in a few days. if nothing improves, then it is NOT the paste, but DC-DC converter (as I suspect). Could be beneficial for the other 4 machines I am expecting (if new paste works), hence the incentive.
Here is paste comparison:
http://www.eteknix.com/arctic-cooling-mx-4-thermal-paste-review/5/
I have some MX-4 coming along with several small heatsinks for the dc chips as well as the r47s.
If capacitive paste is the issue the fix is more in properly cleaning the boards before the reapply.
I have one machine with a blade running 4 degrees cooler than the other. I just opened it up and found that the outside heatsinks were a little on the loose side. When I probed the r47s and the black chips above them, I found the temps to be between 90F - 102F on the R47s and 93F to 111F on the black chips. I'll be trying heatsinks before too long.
Temps were coolest near the intake and warmest in the middle of the unit.
Ah, and now after tightening my heatsinks, I have a 5 degree temp difference in blades, instead of 4 degrees. It started to drop from 440GH/s to 420GH/s earlier today. Now it wants to stay there. Maybe it is due to the paste. Bitmain had made the recommendation to swap the paste, to some people.