I think it does. Otherwise tuning vardiff would not exist.
On wemineltc I am receiving various difficulties ranging from 64 to 600 depending on the particular rig's hashing power.
Taking into account that there is only one server in US and reject ratio is high due to latency I suspect that that it matters even more.
Currently i see across all rigs that difficulty is set to 512. Might be hard coded value.
Since clevermining is still in development I wonder what is Terk's opinion.
Should we use separate btc addresses for each mining rig?!
Is he working on sub-workers. Like for example "btcaddress_worker1"?!
Or should we just use one address for all of them?!
What is Terk's preference on this?
Lack of vardiff doesn't affect your profits if you're in for a long term. Vardiff enabled reduces variance, so you will earn your share even if only mining for an hour. With vardiff disabled your variance can be high and if you want to mine for only an hour, you might get a significantly higher or lower profitability than the pool average, depending on your miner's luck during this hour. If you mine for a day or longer though, it will all even out - some hours will be lucky, some unlucky, but at the end of the day your daily results will be the same as if you had vardiff enabled.
Vardiff helps only reducing variance and making you feel better as you see consistent results every hour. It doesn't help anything else. So it's not really my priority as I have lots of other more urgent things to implement. If you understand that your daily results are not affected, you shouldn't panic seeing your reported hashrate going up and down every hour.
You can use the same or different addresses for each rig - it's up to you. If you need to track individual rigs results then using separate addresses is currently an only option. If you don't need that, it's probably more convenient for you to just use one address.
Sub-workers feature is on my nice-to-have todo list. It has even lower priority than re-enabling vardiff.