Will using the strap option likely make the card run hotter? Or is it just an efficiency thing?
I use '-ethi 0' (Ethereum intensity) so my card runs cooler for various reasons. Will using '-strap 1' with '-ethi 0' cancel each other out? Basically I'd like to use the strap option but not if it will make the card run hotter.
Yes it will use more electricity and it will run hotter. How the ETH algo works its mostly limited by the memory speed. So most of the time the GPU is not doing much since its waiting for the memory to complete its job. By changing the memory straps the memory runs faster and is able to provide the GPU compute the data to analyse quicker, so your speed increases from like 23MH/s to 30MH/s (if RX 570). Since the GPU uses more resources it uses more power and hence runs hotter.
This is actually why it was possible to dual-mine with ETH, because the GPU didn't do much most of the time and it was possible to mine at full ETH speeds while also dual mining other coins like DCR or SIA or PASC.