Thanks for help people! Got the Claymore up and running last night.

It does use a bit more energy, but in my case I don't mind. I'm using the rig to heat a part of my home and xmr-stak's 780W wasn't enough to have a nice temperature in a big room. Claymore's 950W is better. I just love the idea that heating produces income!

Thanks, then there must be something wrong with my input to the config file.

This might be a newbie question but i'll try anyway:

Can you mine sumo with claymore Cryptonote gpu miner?

The reason I'm asking is that after an annoying windows update my old version of xmr-stack doesn't work anymore and the latest version has a MUCH lower hashrate (WTF?!?), Claymore still gets best hash with monero, but it doesn't seem to work with sumo.