Sorry I meant flashing your graphic card bios so that your cards use less power.

GPU tweaking follow the philosophy of less is more :D

Your card has 2 bios on it, press the button on top to access the 2nd bios and turn on a blue led. This way if you mess up you can always depress the button to go back to the original bios.

Read the following guide on how to tweak it
[url=http://www.cryptobadger.com/2013/10/undervolting-in-linux-via-modified-bios/]http://www.cryptobadger.com/2013/10/undervolting-in-linux-via-modified-bios/[/url]

Basically you get usb key and format it so you can boot from it.
Put the atiflash program on you key and boot it up.
Rip the stock bios then restart and boot into windows
Make a copy of the stock bios then use VBE7 to open the rom and modify to voltage.
Save the rom on usb key
Boot into dos again and use atiflash to flash the modify bios

Im running my card at 1.087 voltage compare to 1.2 stock

Ah yes sloppy reading, Cheers

Download CGwatcher and under schedule you can set the time for it to mine.

[url=http://www.cryptobadger.com/2013/10/undervolting-in-linux-via-modified-bios/]http://www.cryptobadger.com/2013/10/undervolting-in-linux-via-modified-bios/[/url]

Follow the step and flash your own bios that you rip, its much safer and efficient I believe.

For the 7950 im undervolting to 1.087 and getting 630 kh per card at 68 degree with an external fan.

Congrats on your first rig! a few tips now that you got your feet wet :D

Your RPM per fan is way to high (3600 rpm!). While the temperature is at the range where you want it to be (70), it might be better to use an external fan to make the video card work less hard.

Then when you feel brave, flash a new bios and cut power consumption by 15%

Here something you should aim for :D msg me if you need any help getting to it.
[IMG]http://i.imgur.com/Md9Cgi9.png[/img]

I have 4 Gigabytes pushing out 720 kh per card under 2000 rpm thanks to flashing the bios to 1.050 volt… if you are not afraid of flashing I would highly recommend the gigabyte with a seasonic 1250

Got my Gigabyte r9 280x recently and put 4 of those sucker in a rig…

Stock Voltage = 1.200 and getting 735 hash per card = 1300 watt

Reduced Voltage = 1.075 and getting 710 hash per card = 1000 watt

Lost 2% performance, gained 23% power efficiency :D and stock fan are running 2000 rpm.

No point squeezing max hash rate.

[i]- Does the CGMiner command --gpu-vddc works for those R9 280x cards? Cause I’ve tried it but apparently nothing happens.[/i]

I dont think so, I use either trixx or afterburner to do the tweaking

[i]- Does CGWatcher recognizes the voltage changes made with Trixx? Cause I’ve changed the voltange on Trixx but starting CGWatcher it shows the normal stock voltages.
[/i]
CGWatcher doesnt recognize the voltage change unless you flash it, so if you change with software you will need to use GPU Z to detect the change in voltage.

[i]- Does overclocking has sense in conjuction with undervolting?[/i]

Yes you can overclock by increasing power and GPU but with mining less is more.

What is your temp for the card you are running?
open case or not?
what is the psu you are using?

Dont touch memclock and just touch GPU and voltage

In my opinion Hash rate is not the end game, instead power consumption, efficiency, and stability is more important.
When you start running multiple rigs 100kh or even 1000kh lost is not as important as stability.

Hi everyone, Since I got good feedback on my Dual X guide I will update my feedback on using the Sapphire Tri-X with SKU - (11221-08-40G)
I upgraded to these model because you can undervolt them, they are as cheap as the Dual X now, and better build quality.

Software is standard: Cgminer 3.7.2, CG Watcher 1.3.3, CG Remote 1.0.7.3
Overclocking I now am using MSI afterburner, I prefer it over Sapphire Trixx.

MSI Afterburner Version 2.3.1
[url=http://event.msi.com/vga/afterburner/download.htm]http://event.msi.com/vga/afterburner/download.htm[/url]

For Remote control of individual computers I am using Sun Login
[url=https://sunlogin.oray.com/en/]https://sunlogin.oray.com/en/[/url]

Combined with Wakeup on LAN I never need to touch each computer again

Updated the hardware list.
CPU - Amd A6 5400K (Using Amd FM2 socket now)
Motherboard - Asrock Fm2A88 Extreme 6 - Extreme 4 are hard to find plus it has an input for a 4 pin molex to help power the PCI slots.
HardDrive - 32gb SSD
Ram - 4 GB DDR 3
GPU - Sapphire R9 280x Tri X (240 Euro!)
PSU - LEPA G1600 / Enermax Platimax 1500 (250 Euro / 300 Euro) - PSU is the most important aspect of any rig, dont go cheap! Seasonic is very good as well.

CG Watcher Config Setting :

“intensity” : “13,13,13”,
“vectors” : “1,1,1”,
“worksize” : “256,256,256”,
“kernel” : “scrypt,scrypt,scrypt”,
“lookup-gap” : “2,2,2”,
“thread-concurrency” : “8192,8192,8192”,
“shaders” : “2048,2048,2048”,
“gpu-engine” : “1050-1050,1050-1050,1050-1050”,
“gpu-fan” : “0-85,0-85,0-85”,
“gpu-memclock” : “1500,1500,1500”,
“gpu-memdiff” : “0,0,0”,
“gpu-powertune” : “0,0,0”,
“gpu-vddc” : “1.050,1.050,1.050”,
“auto-fan” : true,
“temp-cutoff” : “85,85,85”,
“temp-overheat” : “82,82,82”,
“temp-target” : “75,75,75”

MSI Afterburner setting:

Voltage 1.050

Here is my result:

[IMG]http://i.imgur.com/sx3bzTk.png[/img]

730 KH for 1.050 Volt running with an simple external fan. 2 Cards in Slot and 1 Using a riser, will upgrade all to riser this weekend which should greatly reduce heat and update the result as well.

Basic setup is 8 Computer with 3 cards each. (Finally got all my risers, will be 4 card each)
Overall monitoring using CGRemote, with CGWatcher on each computer with auto restart and monitoring alert
Individual access using Sun Login combined with a Netgear network switch.

TIPS:
Depending on your wiring, an electricity socket can handle maybe max 3000 watts, dont run more than 2 rigs from a socket or you will trigger circuit breaker!
Power is key to stability, 5% increase hash for 10% more power aient worth it.
You can connect a X1 to X1 riser to your Graphic card… :D