I don't think it would matter, but I could be wrong. The only difference I think aftermarket cards has is just the heatsink/fans/cooling method (so better overclocking abilities). But with my underclock/undervolt settings, the reference cooler is already keeping it cool even in a hot garage style and I'm not trying to overclock.
I believe the reason why most people would want the aftermarket cards is just for better cooling and overclocking ability and overclocking=more power usage. So since my main goal is to reduce power usage and since I'm running on 110v, I can fit 2 rigs on 1 outlet without tripping the circuit breakers.
Our residential home has a 15amp circuit breaker, so if I overclock for maximum hashrate, it could run to around 1000 watts per rig. And if I place 2 rigs on 1 outlet, it would definitely trip the circuit breaker since it would be 2000+ watts.
that is the reason I buy cheap XFX R9 390 cards and under volt and under clock to get the best efficiency.
I heard that 390 is power hungry and is still using lots of power even when underlocked and undervolted (which many cards cannot even do? - is XFX an exception? In ethos i did not find a way to undervolt my VTX3D 390...)... which settings do you use, and what is the power usage you are seeing per card/rig?
To remain on the rx480 topic... I managed to get down to 890W usage for a whole rig with 6 cards... getting 25MH per card, and my wattman settings are simple just -20% core clock (memory at 2000).
I tried boosting memory to 2250, where cards produce 27,5MH.... but this rises power usage for the whole rig to 1100W. This is 210W more (or 35W per card) which i think is too much (+ less stable, + have problems removing the heat)...
yeah for now I am just using wattman on my 480's with -23% I do 24.5mh with a little less power then you.
I did try more aggressive settings of pikachuy for undervolt and for memory and got low not as low as him but pretty good. 270 watts 2 card setup 23.5mh
I went for more and crashed the system and I can not get back into wattman to change the settings.
This is okay as I have 6 pc's ready for 480 cards so I moved the cards to another system and I will try to figure out why the wattman files come back after I delete all amd 16.7.1 and installed it back. I thought this would reset the wattman settings but it does not.
So there must be a file outside of 16.7.1 that holds on to the wattman settings.
So if you or anyone sets voltages to low and can't run the system you may not be able to clear the wattman settings very easily.