Not sure what it is. Let's see if it helps when the new server version is up and running.
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Hey Doc, some advice/tips from a webmaster/game developer...
You need to UPGRADE your server, one PH/s I lose too much hashing power because of traffic bottle-necking, too many connections. Tried your pool for a week today and I am disconnecting today too due to having too great of a hash power loss compared to when I joined when you were below 1PH/s. I'll assume you're hosting online, most hosts can do an upgrade in an hour or so.
That's why you're having such a hard time to find blocks as of late, you're not using the pool's complete hashing potential I am afraid. I observed about 10%-20% average hashing power loss using your pool compared to other modern, non-beta pools I have tested. Has nothing to do with the recent difficulty increase, made really little to no difference.
I noticed the difference the minute BMT went back over 1PH/s and kept growing on it. I monitor my workers like a hawk, so I know in real time what's going on, at all times of the day and when your stats show almost 50GH/s difference from my miner's interface to yours for most of the time, I start asking questions because that's rather significant, in my book anyways. Connection is steady though.
Your server needs a hardware upgrade and maybe very well, bandwidth.
Sorry but I can't mine here with only having 400GH/s with a 50GH/s loss due to bottle-necking. People buy machines that clock at 50GH/s, right now it's like I have one of those and your pool's rejecting the whole thing.
I hope you take from what I just said, lots of people pay good money for my advice. But again, my knowledge on mining is still rather rudimentary but my knowledge on making money, computers and web design is spot on =D
I mean, it's not just your pool with bottle-necking but I actually like BitMinter... well used to thus so far anyways. Maybe it's just me? I doubt it, your pool does stand out in the bottle-neck column. That's why i don't hash with GHash anymore, bottlenecks and gaps were too great during the day.
Peace out