I just started and have a few of the MSI 280x but have not jumped in on this myself, yet. This blog has details for undervolting the card... http://rumorscity.com/2013/12/20/radeon-r9-280x-litecoin-mining-and-sweet-spot-for-700khashsec-part-2/

Also, you can try Trixx. Some of the MSI 280x can be undervolted using that tool (mine cannot.) https://www.sapphireselectclub.com/ssc/TriXX/ Nevermind, saw you're using Linux.

Really wish I'd seen this thread earlier, sigh. I ordered a few of these to test with back on 12/20 and they're still sitting in China Post, "Preparing shipment."

So then I thought I definitely wanted a design that used these, and decided to just buy the full qty since there's a return policy, seller has good reviews, etc. So I ordered a dozen more on 12/23. They were received today (Friday) via DHL. 

So I paid $30 ea., but at least shipping was free.

Sweet rig!

So if I wanted to use the USB 3.0 riser cables (to allow some creativity in the build) along with the new ASRock H61 mining motherboard that's posted in the OP, would I just use the powered risers as designed and not plug in either molex on the motherboard? I'm assuming so but want to be sure.

Thanks for the thread, ssateneth. Very cool.

Transfer yesterday into my wallet for +0.00155 BTC!!

The sky's the limit!

Very glad to have found this community, bunch of great people from what I've read.

And I've read a lot,,, been on Holiday for nearly two weeks or so and working (reading/researching & procuring/building/configuring systems) at this coin thing a LOT harder than I do my day job, lol.

Happy Holidays, everyone.

Have you checked the main thread? Over here:
https://bitcointalk.org/index.php?topic=259649.3280

Things seem to have been a a bit up and down these last days but everything is eventually flowing as it should. If you read the last few pages of that thread you'll get the drift.

Thanks!