fluctuations are indeed normal; it depends on the miner if they display it correctly or not
vdd is core voltage
mvdd is memory voltage
An update to my wattage testing:
I was wrong, fan speed does not take a bite on the wattage.
I tested de Liquid Cooled one, and compared it stock and vega 56 flashed. Same power supply used, Corsair Bronze
ASUS STRIX:
Hashrate:190MH
Reported consumption: 140W
Real consumption: 200W
Gigabyte GOC
Hashrate: 166MH
Reported consumption: 165W
Real consumption: 185W
Gigabyte Vega 64LC:
Hashrate: 148MH
Reported consumption: 137W
Real consumption: 190W
Gigabyte Vega 56LC (flashed):
Hashrate: 190MH
Reported consumption: 146W
Real consumption: 212W
Note1: same OC as the asus, i will fine tune it later, i just want to test wattages
Note2: after the conversion to 56, same 64 OC settngs, same real wattage but 176mh
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I have a theory that the risers pull 20-30 watts for two reasons
1.
I have one server PSU that powers risers and GPUs.
On a different rig ATX powers all the risers and the server PSU just powers 4 cards. I monitor the wattage on those server PSU and when I move cards from the one with risers to the ones with out seemed like roughly 20-30 watt difference
2.
I never put 3 risers on a single sata, I do 2 risers per 
, but my buddy always runs 3 risers per sata and burns out a riser like once a month. (SATA power cables rated at 57w)
The fact that that your Gigabyte is off by 20w makes me think I am right
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Note that a bronze PSU will be about 10% higher wattage than plat PSU (85% efficiency vs 94%). So taking 10% off your numbers would help normalize to server PSU or typical miner PSU. Thanks for the numbers, LC much higher as I was suspecting. Gigabyte air seems to report fairly accurate actual power demand, accounting for efficiency loss. My rule of thumb has been 200W per vega and that seems to hold true here.
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Risers can pull 75W. Sata rated for 57W. So even one riser on a SATA is bad. They may pull 20-30W by default but if push comes to shove in demand theyll draw more. Risky using them period. Molex cables about $5 and enough evidence out there they can supply 75W minimum. Thats what i use for ATX one riser per cable. Server PSU non-issue of course. The gigabyte being off 20W is because of PSU efficiency loss. Card wants 100W, bronze PSU needs to draw 115W ish to actually supply 100 after loss.
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One anecdotal evidence: my 5700s draw about 140W wall. Server PSU i provide 2 75W connectors, one to riser and one to 8+6 pin input on a splitter. It gets 75W through the 8+6 input and has to get remaining 65W through the riser. Already over 57W there.
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Interesting I never thought to use the cables that way, I’ve always built to put minimal power through the riser and tune the cards so they pull less than the power cables are rated at. Good to know I could pull some extra watts through the riser If I go over the power cables limits… if I stop sharing cables for risers lol.
Hmmm… Damn, my PSU blew last night and took my SSD with it. I had to temporarily use a USB to keep the mining rig going with HIVEOS.
When I rebooted, my cards were all fine, but my VEGA 64 FE won’t go higher than 151 mh, whereas previously it would get to 165.1. It’s also very unresponsive to different changes on HIVEOS I can change the core and the memory by 200-300 and the mh doesn’t move…
Any ideas on what I can do?
Thanks
Damn! What is the new PSU you are running now? Could be not giving is as much power as the last set up if the hash dropped and OCs wont improve performance past a certain point, 64s are power hungry.
What PSU was it that blew up, any idea how much it was pulling?
The PSU was an old 750W. I’ve bumped it to an 850W now.
Hmmm… Maybe I’ll try plugging it into a different slot on the mobo…
I was hoping it was the cause I was using a USB rather than a SSD.
could be USB for sure ive seen alot of really strange issues fixed when people switch to SSD guess we will know soon
surge from PSU failing may have damaged riser. Ive had a riser cause that issue before. Easy quick check is swap 2 cards and see if problem follows
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That is such a good freaking idea. I’m going to replace the riser and try it out tomorrow. Thank you.
This info is true but just a little clarification to avoid confusions.
Sata and Molex cables usually are exactly the same and can handle a lot more, the power limit is not in the cable is in the connector.
I use molex connectors for my risers, but there is not a standard in how many watts they can handle thats why people always recommend using only pcie.
And of course i will never use SATA
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Bro, how’s your Vega 56 Red Devil - Hynix? Would you mind to share stable setting and straps? It’s been a headache to manage this cards… in ETH preferably. In few hours, TRM detected dead on the card.
Grateful for your help.
Cheers…
best i can do for my hynix red devil vega is 46.83 MHS (stable) with settings
CORE : 1000, VDD : 850, MEM : 910
straps :
amdmemtweak --CL 20 --RC 36 --RP 13 --WR 11 --CWL 7 --FAW 12 --RAS 23 --REF 65535 --RFC 164 --RTP 6 --RRDL 4 --RRDS 3 --WTRL 4 --WTRS 4 --RCDRD 19 --RCDWR 11
if the card crash after a few hours usually i add more VDD (increment 10)
also don’t have the patience for this card 
I end up selling it to my friend
my friend settings :
CORE : 920, VDD : 800, MEM : 907
straps :
amdmemtweak --CL 19 --RC 36 --RP 13 --WR 11 --CWL 7 --FAW 12 --RAS 23 --REF 65535 --RFC 249 --RTP 6 --RRDL 4 --RRDS 3 --WTRL 4 --WTRS 4 --RCDRD 19 --RCDWR 11
achieve 46 MHS 94 watt
thanks bro… will try that setting…
Careful with that.
I always learned that you needed to power a single card from the same source, so both risers and card’s power connectors from the same PSU.
If you use 2 different power sources units, they might give (slight) differences that might ruin your cards.
Don’t know how much of it is true, but I haven’t taken any risk.
I thought it was even merely 45W.
Anyway, not a single SATA in my rigs due to that reason!
Also only few Molex; most are 6/8 pin PCIE connectors.
Maybe it has a different hiveos version or kernel?
Hi bro, not to nag, but this is an ERGO specific topic; there are already 3 other topics with a lot of Vega info for ETH:
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Ya I would avoid molex but even a 1300W EVGA PSU only has 6 PCIE 8 pins. I would need 2 8 pins for 4 risers so I would only be able to power 4 cards for a 1300W PSU. Havent ever heard of issues with molex but no one can seem to find a spec that definitively says it can handle XXX power. Since people “believe” it is 145W I just do one molex per riser and even if they are off I am set. I have a 50% margin of safety at max draw so I am ok with that.
Also, you power the riser and GPU with the same PSU mainly so if one goes out you are not causing a voltage differential at the riser to GPU interface. Also important that the two PSU are connected to same phase outlet. Breakers use two out of phase 120V inputs and that is how you can get 240V (american standard of course). This means different breakers are out of phase and have 240V potential to each other. I use a riserless mobo and would fry something if one of the two PSU were out of phase or one off and one on, cant adhere to the standard. I use a common ground that shuts them both off if one isnt on. Need a PhD to do this stuff i swear
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Im inclined to believe you as they always failed at the connector, where resistance will be the highest, but I am not sure how a connector could have less capacity than the wires they support. I’m not educated enough to argue one way or another, just not sure how functionally that would be.