your xfx is voltage locked at 1.17 when other people are running 1.0 to 1.05 volts, so your card will always run above 80 degrees, probably 85 degrees if the case is open and you put a fan on it, otherwise maybe even over 90 degrees.
best thing to do with that card is to flash it to the gigabyte bios, keep your case open and have a fan blowing on the video card.
its one of the worst cards to mine with in my opinion but you can easily get 730 khash on it with core at 1080 and memory 1500.
Topic: Please help with R9 280x XFX best setting ! (Read 870 times)
XFX r9 280x is one hell of a crap card... they are voltage locked on maximum voltage (1.26) and i have a really hard time running them around 83° C, 1020 core, 1500 mem (ambient temperature is hot here, 35° C). But, i will just keep em running until they die since they have lifetime warranty.
i have try many setting but my gpu run at 80 c or 82 c
please anyone provide me good setting 
There are worse places to start than here: https://bitcointalksearch.org/topic/how-to-optimize-your-videocard-for-hash-speed-low-power-and-safety-442274
Here. CGMiner is crap, use SGMiner 4.0.0.
I'm using the same settings except for the engine clock.. more than 1100 is a bit extreme, I usually run at 1040, undervolted too. (710kh on sapphire dual-x) 
Here. CGMiner is crap, use SGMiner 4.0.0.
Bought 2 GPU today those are R9 280x XFX ! please someone tell me best setting for Cgminer to run 2 GPU
so i can get good speed !!Thank you !
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