Bitcoin Forum

Finally thinking about making a rig of 2X Gigabyte r9 280x,
can anyone tell me whats the max khs you can get from these cars when Overclocked?
and what kind of wattage psu should I be getting to run 2 of these cards (obviously I want as low w model as possible so its cheaper)?



Also What kind of Power Supply do you think would 3x R9 280X need?
I see a good 750w would be good for 2X r9 280x.
but how much would 3 of these cards need?

https://litecoin.info/Mining_hardware_comparison   ----They give a good comparrison of them, do Ctrl-F to open the find function then type 'r9'280x' then it will go straight to the cards, it also tells you the speeds, drivers software used with the cards to get them running at that speed.

You could probs go even higher than them if you OC higher (but that would usually require watercooling if you want to go higher than these as these are already pushing the speed of the cards)

570-800 K/hash (approx)

Give that link a read though, although personally I would go for the MSI OC edition 280x

730 kh/s

around 650 watts for 2 and a 45w cpu.

if you can get them above 700kh/s that would be very good.

I have 2 running with a wall plug too measure, idle system draw is 38watts without any gpus installed, with both GPUs undervolted and mining I'm getting 546watts from the wall using gold rated PSU, @ 720khash/s off each card. Without undervolt 673watts from the wall.

https://i.imgur.com/PUMTOF2.jpg

between 720 and 750, depending how much im doing on the pc. They are running with a 680w bequiet 80+ bronze psu.

these are my settings:

 -I 13,13 --shaders 2048,2048 -g 2 --gpu-engine 1070,1070 --auto-fan --temp-target 75

im Running 740/750KH/s with a Asus 280x DC2 Top

setx GPU_MAX_ALLOC_PERCENT 100
setx GPU_USE_SYNC_OBJECTS 1
cgminer.exe --scrypt -o stratum+tcp://server address here -u worker name here -p password here --shaders 2048 --thread-concurrency 11200 -I 13 -g 2 -w 256 --gpu-fan 85 --lookup-gap 2 --gpu-engine 1080 --gpu-memclock 1500

I have Gigabyte R9 280x Rev2

I undervolted them 1.075

mining 720-730 for both cards.

This is the settings I use

cgminer --scrypt -o stratum+tcp://yourpool:3333 -u yourwoker -p yourworkerpass --thread-concurrency 8921 --lookup-gap 2 --gpu-engine 1049,1049,1049,1049 --gpu-memclock 1500 --gpu-powertune -20,-20,-20,-20 --gpu-fan 75 -w 256 -I 13 -g 2

Thanks for the info.  Definitely under consideration for my new rig.

I wasnt this far :D

https://i.imgur.com/4gEtG1n.png

I'm using mostly the same on my Asus Top cards, with 1081v in trixx(1012v in GPUz) and 1030 for gpu-engine.

some cards are better than others, all should do 700 KH/s or better.

I have xfx cards that suck, MSI are ok other than fan rattle.

most ppl liking asus, sapphire

try to look up and see the model #s from litecoin mining hardware wiki to see which ones are popular.

ASUS 280x DCII TOP ~750-760 Kh/s

Why not r9 290x?  8)

not optimized for cgminer

dunno about bfgminer, that card should do above 1mh/s

I can buy 2 r9 280x for the price of 1 r9 290x, lol.


What kind of Power Supply do you think would 3x R9 280X need?
I see a good 750w would be good for 2X r9 280x.
but how much would 3 of these cards need?

1000W is fine

I think ASUS and MSI cards can average a bit more but every card is unique
so you will always get slightly different result even with same cards.

I have this gpu in rev. 1.0 and it averages 722kh/s

This guy have a bit better results with rev. 1.0: http://www.youtube.com/watch?v=RnsG0HY_yqg

Also check out this video with rev. 2.0: http://www.youtube.com/watch?v=gVd0zKQ7a8Q

Don't know how he was able to achieve that performance. Only difference between rev. 1.0 and 2.0 should be better cooler on GPU.

http://s21.postimg.org/xrt0kcxo7/Untitled.jpg

2x Sapphire Vapor-X.

C:1080 M:1500

cgminer: -I 13 -g 2 --thread-concurrency 8192

NIIICE!


What kind of Power Supply do you think would 3x R9 280X need?
I see a good 750w would be good for 2X r9 280x.
but how much would 3 of these cards need?

What kind of Power Supply do you think would 3x R9 280X need?
I see a good 750w would be good for 2X r9 280x.
but how much would 3 of these cards need?

can i harm them with undervolting? does powertune have any considerable effect?

Undervolting no, just crashes if you take it too far down vrs clock rate. If anything your decreasing your time before failure, lower volts mean lower temps for GPU core and VRMs, not too mention the power savings over 24/7/365 use, the trick is finding a sweet spot your comfortable with, I've read one guy was running at the low end of 1v 960ish core for 670khash. not sure about powertune i'm using -20 and haven't played with it.

Got 2x R9 280x -> 720kh/s each  at 530W both.

cool,what kind of brand are they? also overclocked?

also What kind of Power Supply do you think would 3x R9 280X need?
I see a good 650w would be good for 2X r9 280x.
but how much would 3 of these cards need?

I've shared my settings here:

http://forum.feathercoin.com/index.php/topic,6396.msg47680.html#msg47680

Got 1050W GOLD PSU.

Could any one can tell about full assembling, each and every parts. Please that will be helpfull for newbs like us.

Do you think I could run 3X r9 280x cards on a 900-950w PSU?
each card seems to take 250wats X 3= 750 and I would have about 150w left for the rest of the system.

Only if you purchase a good GOLD one. I've had a bad one before - 850W and it couldnt even push out 580W without dying..

http://www.extreme.outervision.com/psucalculatorlite.jsp

Use this tool to calculate approx. W needed.

Really if you can get 7950's so much nicer to work with, i have both types. Some get the 7970 to decent hash/kw and good temps, but most people i have come across like the 7950's more.

Mine run easily at 670kh and much cooler and consume less electricity.  The 7970's go to 750kh but i have temp issues and way more problems over all.

wtf amd did not bring out the 280 i have no idea.