I've been mining for the last week or so while taking time off to play games with friends. I am running my 7870 at 935 core and 1580 memory and running my R9 270 at 1000 core and 1500 memory at 17 and 18 intensity respectively.
I was getting around 390kH/s with my single 7870 and with the addition of a R9 270 I get around 800kH/s which runs for 24/7 completely fine, one problem that I'm not sure actually is a problem is that I get a butt ton of artifacting!
It's not a problem really as I usually am not even in te house when mining but was just wondering if artifacting while mining on the limits of semi-stability is bad or worse for the card than just mining at stock frequencies.
And yes a guide from someone who's been doing it longer than most of us would be much appreciated by me and I'm sure many others.