Bitcoin Forum

I've got a few BE's and Blades that I've been using to mine various Alt Coins.

I get a very large number of Rejects and I believe it's due to expiry and scan time settings of my instance of bfgminer.

Does anyone have some tips? Maybe it's the pool?

What coins are you mining?

ZET and TRC mainly

GBT / stratum ?
Using getwork for such rapid coins makes no more sense, your miner will get notified of new blocks way too late, leading to this high number of rejected submits

Sorry for the lack of that info.

I am using stratum pools

i'd then personally contact the pool admin an ask him if he uses a blocknotify command instead of just relying on gbt data to detect new blocks.
(This should be quite obvious to any pool admin, but .. )

If he does not use blocknotify to notify his pool of new blocks, his pool just "wait" for the next getblocktemplate call to detect new blocks, what will lead to late detections.

note that if this pool have a poor connectivity to the coin network, using blocknotify will not change anything : his pool will always get notified way too late.
The first basic check you can do is try to find if at least one of the pool TRC|ZET daemon nodes have opened p2p ports (otherwise he will rely on outbound connections to detect new blocks, adding quite some time to the process).

Then, if choosen pool
* does not use blocknotify
* or have no open TRC|ZET p2p port opened,
just switch to another pool :)

Very helpful, Thanks!