3 x 280x what PSU would i need?
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[quote name=“svennand” post=“37729” timestamp=“1385773013”]
seasonic x1050, with x1250 you could use 4x 280X
[/quote]Ditto. If your motherboard has room for another card and if you can find it anywhere, I would go with the x1250. You may want to add another card sometime down the road…maybe sooner than you think.
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At a maximum you will need about 310 watts per 7970 getting the max KH/s rate. However, I have started mining for electrical efficiency and need only 180-190 watts per 7970 and I still get 660KH/s with these lower settings.
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Hi,
I heve recived 2 shappire 280X OC , how much Kh/s do you have per card ? I have to prove them. I also have 2 7990 mining perfectly 1.280Kh/s each.
Go FTC !!
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[quote name=“Endika” post=“39065” timestamp=“1386073217”]
Hi,I heve recived 2 shappire 280X OC , how much Kh/s do you have per card ? I have to prove them. I also have 2 7990 mining perfectly 1.280Kh/s each.
Go FTC !!
[/quote]i purchased 5 of these and have been working with one to tweek it. got it to 740kh/s but it wouldn’t accept shares currently running it at 650. just got them in last night so haven’t had much time to work on them
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[quote name=“RIPPEDDRAGON” post=“38784” timestamp=“1386005347”]
At a maximum you will need about 310 watts per 7970 getting the max KH/s rate. However, I have started mining for electrical efficiency and need only 180-190 watts per 7970 and I still get 660KH/s with these lower settings.
[/quote]what do you do downclock the voltage?
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I’ve received my 2nd r9 280x this week and here are some wattmeter results when running 2 cards.
The cards themselves are running@stock clocks.[img]http://uaibe.com/stuff/mining.r9-280x.01.jpg[/img]
[b]edit:[/b] I had to upp the voltage to 1.07v (Trixx setting). @1.05 the driver crashed after about an hour. The cards are now pulling ~470watts. Still good =)
Btw FYI GPU-Z 0.7.4 is showing 0.98v @ Trixx setting 1.07v … not sure which tool is right *lol
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+rep. glad youre sharing!
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[quote name=“nimmneun” post=“39320” timestamp=“1386118180”]
I’ve received my 2nd r9 280x this week and here are some wattmeter results when running 2 cards.
The cards themselves are running@stock clocks.[img]http://uaibe.com/stuff/mining.r9-280x.01.jpg[/img]
[b]edit:[/b] I had to upp the voltage to 1.07v (Trixx setting). @1.05 the driver crashed after about an hour. The cards are now pulling ~470watts. Still good =)
Btw FYI GPU-Z 0.7.4 is showing 0.98v @ Trixx setting 1.07v … not sure which tool is right *lol
[/quote]wow my sapphire r9 280x vapor x are pulling 720 watts while mining. everything i read is that that my cards use 300 watts. apiece. system idl was 110 watts but this is my regaular gaming rig that has a 165w proccer in it. will be pulling them out soon as i get another board or chip.
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yea all those hdds / fans / big cpus add up.
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well the bare bone system i have with a 65w processor is still pulling 720 to 750 with 2 r9 sapphire vapor x
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[quote name=“nimmneun” post=“39320” timestamp=“1386118180”]
I’ve received my 2nd r9 280x this week and here are some wattmeter results when running 2 cards.
The cards themselves are running@stock clocks.[img]http://uaibe.com/stuff/mining.r9-280x.01.jpg[/img]
[b]edit:[/b] I had to upp the voltage to 1.07v (Trixx setting). @1.05 the driver crashed after about an hour. The cards are now pulling ~470watts. Still good =)
Btw FYI GPU-Z 0.7.4 is showing 0.98v @ Trixx setting 1.07v … not sure which tool is right *lol
[/quote]by the way was that mining?
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dropped the voltage down to 1.11 and they dropped to 550.
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[quote name=“colsteel” post=“40301” timestamp=“1386280381”]
by the way was that mining?
[/quote]mining like a champ =) still up and running @ 1000mhz/1500mhz. it does seem stable. I’m going to test 1020 on the core now for the next few hours. Trying to find a decent voltage sweetsport for 700khs.
edit: try tiny steps first. @1050 I could only go from 1.163v (stock) to 1.131v, then the khs startet bouncing.
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I just got my 3X Sapphire Dual X R9 280X OC cards stable after alot of tinkering. I still haven’t tried to tweak cgminer for better results, just getting them stable was a chore.
I also have 2 msi 7950 reference cooler cards there as well.I had planned for a 6 GPU setup, but 2 of the powered risers i bought from ebay did not function right and caused all sorts of lockups.
I had 2 corsair RM 750 watt power supplies using a 2x PSU adapter. Worked well, once I got the cards running full speed the 3X 280X cards were drawing 850 watts at stock volts. So i switched it up to run 1 7950 and 1 280x with the main-board/components and 1 PSU to run 1 7950 and 2 280X cards. Now the system is stable.
In conclusion, i would definitely use a 850-1000 watt PSU per 3 280X cards. Make sure it is gold plus or platinum for efficiency and preferably a brand with good reviews and rated to run 24/7 at 80-90% loads.