While I think reducing block size would help a bit and I had a couple other ideas for reducing orphans, I believe Sturle's idea in combination with propagating blocks outside the bitcoin peer-to-peer network could make orphans nearly extinct. So I think that is the best way forward, for all pools.

I'll see what I can do. Stratum testing will hopefully begin soon. After that I have a few pressing matters of which the orphan problem is one. Priorities, priorities ..

Thanks for the support, guys, and thanks for running the numbers, philipma1957.

I'm trying out BitMinter's GBT server for the first time, and got strange rejects on cgminer 2.9.5 almost immediately:

 [2012-11-28 00:50:30] Rejected 33f2f1eb Diff 4/4 GPU 2 pool 0 (unknown-work)
 [2012-11-28 00:50:38] Accepted 3b537d2f Diff 4/4 GPU 0 pool 0
 [2012-11-28 00:50:47] Accepted 387a7e01 Diff 4/4 GPU 2 pool 0
 [2012-11-28 00:50:57] Accepted 34475128 Diff 4/4 GPU 2 pool 0
 [2012-11-28 00:51:03] Accepted 378ea469 Diff 4/4 GPU 0 pool 0
 [2012-11-28 00:51:46] Accepted 1c1a6472 Diff 9/4 GPU 1 pool 0
 [2012-11-28 00:51:47] GBT LONGPOLL from pool 0 requested work restart
 [2012-11-28 00:51:49] GBT LONGPOLL from pool 0 requested work restart
 [2012-11-28 00:51:57] GBT LONGPOLL from pool 0 detected new block

As you can see, it comes seemingly in the middle of a block. I can't get a clear understanding of what's wrong with those, since a similar problem was supposed to be fixed in 2.9.4.

I stopped having those rejects after changing all my rigs to BitMinter GBT. Could be just bad luck, but is it possible that having difficulty change dynamically may cause that kind of rejects? I don't have a good understanding of how dynamic difficulty works. At first the difficulty hovered around 1-2, but after pointing all the rigs at BitMinter GBT it's been stable at 4.

EDIT: Now my share difficulty went up to 8, and dropped back to 4 soon afterwards. If my hashrate is just about at the threshold between 4 and 8, at least I'm testing the dynamic difficulty thoroughly.

Yup, it's been changing between 4 and 8 for some time now.

I haven't seen the difficulty go down yet as we just minted 210001 - hmmm...

Just a question: does Bitminter includes TX fees in the miners payments?
Now after the halvening this is more important.

Doc, are we accidentally still being paid based on a 50 BTC block reward?

"Expected per block" on website corrected to take the reward halving into account.

I also added MPoolMonitor under "tools" -> "third party apps" on the website.

I have some little things still to do on Stratum support. I hope to enable Stratum on the testport within a couple days.

If everything runs perfectly I could perhaps enable Stratum and GBT with var diff on the main pool before the weekend is over. But perhaps delay var diff on getwork a bit longer until hashpower.com supports it.

Also I think ztexminer doesn't support var diff. And perhaps never will?

GBT replaced X-Mining-Hashrate with the "target" request option (BIP 23 Basic Pool Extensions). Stratum has no equivalent (and no HTTP for headers) yet.

A max diff of around 20 would be nice.