I've been keeping an eye on the miners, doing refreshes every so often. Here's what I've noticed. It seems when I drop some MH one of the blade temps rise. Similar effect when I gain some MH, a temp goes down. So it would seem my issue is temperature based.
With that said, if this proves to be right and more time well tell as I continue to watch the numbers.
So... what if any alternative cooling methods can be used on overclocked S3's (237.5 and higher) ?
Interesting - that's how I first noticed my problem, but for me it was more to do with the temperature of the PSU itself. That's what exposed it being "on the edge." But, you don't have quite the GH/s dip that I did, so it could well be the miner. Either way, keep us in the loop to what the final answer is. Good luck!