Topic: Undervolt Minercard? (Read 3225 times)

When it comes to Linux, I'm a bit old-school, mate... all my mining rigs are housed in idiotic wooden boxes and controlled via ssh. The GUI is only ever seen ONCE when I install the OS for the first time... AMDOverdriveCtrl and the ATI Catalyst proprietary drivers are installed from the command line. I run everything from my collection of Macs - I've got a 'Space' (i.e. virtual desktop) devoted purely to my miners, with 8 terminal windows on the screen (it's a 2560x1600 Apple screen... plenty of room... though it's slowed down a bit by the GPU doing mining as well)

Hence I'm using AMDOverdriveCtrl from the command line. If you haven't tried this - do it! Not only does running AMDOverdriveCtrl in batch mode (-b) show you the default settings (core and memory clock, plus core voltage!) but also shows you which 'devices' are active (i.e. most GPUs will have a separate 'device' for each output, whether connected or not - the default is always connected) so you can choose which device ID to program.

I've found that many manufacturers have interestingly different voltages for the same GPUs, and also that all of them (5xxx and 6950) will tolerate a light undervolt and *still* overclock to the previous max overclock. Saves me quite a bit of power at the wall, but more importantly, given my 12-GPU high-density shelf rig, keeps them from cooking.

I'm surprised you're not running AMDOverdriveCtrl from the command line already - do you use VNC or remote X to control your farm? You've got a LOT of hashing power so must have a LOT of boxes...

I'd be very interested to have it confirmed that the tool is, in fact, undervolting the cards like it reports it is... I can't stand ANY tools that report success when they have failed to perform the command...

I'm also running everything through SSH.  I set up static DHCP leases for each miner by MAC address.  I have a startup script on my miner flash drives that checks a small script my web server to get its miner ID (by IP address).  After getting the miner ID, it downloads a script that is personalized to that particular miner.  This allows me to just set up a new rig, plug in a flash drive, boot it, and walk away.  All of the flash drives are identical and interchangeable.  If I were still running around plugging in a monitor into each miner, I'd be going completely mental by now. 

When I first started setting up miners, I was using the GUI though.  I remember never being able to change the voltage on any 6000 series card (with the exception of a couple cards that are actually just re-branded 5000's...  like the 6770).  When I'd change the voltage, the profile voltage would change, but the voltage reported back from the ATI driver would still show the stock voltage.  This is what led me to flash my cards since I do the same thing that you do (overclock and undervolt).  The 6000 series cards can tolerate a pretty serious undervolt.  I'm running my 6970's undervolted to 1.05v while overclocked to 940/340.  They run flawless for weeks at a time.  At stock clocks, I was actually able to keep cards mining stable at slightly under a volt.

I compared AMDOverdriveCtrl versions on my rigs.  They're using the current version.  The voltage wont budge on any of my 6000 series cards.  I remember reading on some forums somewhere that AMDOverdriveCtrl only knows how to 'talk' to the voltage regulator on the 5000 series cards.  AMDOverdriveCtrl supposedly didn't make a call to the ATI driver itself (to change the voltage)...  they actually wrote the necessary commands into the application itself.

Haha.  Hey. 

Hmm...  Unless AMDOverdriveCtrl has changed since I last downloaded it, it doesn't know how to change the voltage.  I mean...  you can change it, but the change doesn't actually take place.  You can see the actual voltage in the far right text box next to the gpu/mem frequencies (not the ones at the bottom though).  Like I said, I haven't updated it in quite a while though.  Maybe support has been added?

Are you sure that the temperature change isn't just from the memory frequency changing?  I'll have to give this a try tomorrow...

^This.

Under windows, you can change the voltage on most cards with MSI Afterburner.  Under Linux, you can change the voltage on 5000 series cards with AMDOverdriveCtrl.  With the 6000 series, you'll have to flash the cards to change them (under Linux).

I overclock and undervolt my personal rigs... Keeps the hash rate up and keeps the cards cooler than stock.  Also saves on power.  You just have to be careful to find the right settings or your setup will become unstable.

The only reason to undervolt a card would be to also reduce clock rate (and hash rate) as you can see significant energy drop with a decent reduction in voltage.  This makes the card more efficient but reduces gross mining rate.  The only reason I see doing that is if you had a situation where @ stock voltage (and power draw) you were barely break even.  Lowering voltage could give you more breathing room.

The main problem for video cards longevity are capacitors (deteriorating faster at higher temperature) and mechanical parts (fan).

If you undervoltage your card too much it might increase the invalid packets rate. Be sure to check it on the pool you are using. Mining alone with undervoltaged cards needs a stability test, or you will waste a lot of time and money.

Undervolting: Thanks for the answers, I found it intersting to read about power cycles and how they wear down the longevity of hardware. As for undervolting, I am positive it wouldn't effect performance of a chip, it just alters the voltage which is needed for the electrons to jump over into another state, or am I wrong?

Cooling: 4x Arctic Twin Turbo Pro and 4x Arctic VR001 and 4x BeQuiet PWM 120mm and Open Window.
Alternative cooling suggestions are welcome! Water cooling is a bit too expensive for 4 cards for my taste.


Longevity and Thoughts: Greed kills. Keep it from a long time, Stock, Future, Forex, Metals, Options Trader. That's why I will do this "just for fun", like the inventor of Linux once stated. I won't push my GPUs to the max. I will sell them later and I want the new owner to be happy not to be angry at me. I pushed my 5850 to 360 Mhash/s without voltage tweeks and its in the burying ground now.

Invest in yourself
The four 5850/70 I bought will make me happy a long time, since I will treat them well. 300 Mhash/s max with lowest memory clocks and extreme cooling. 1-2 hours off time a day. I even gave them names. Mining is just a game and people don't see that easy money NEVER stays with its owner very long. If you want to make money, invest in yourself, go to University, buy a book, heck buy clothes.

GPUs are made to run at stock volts for years! The temps are the biggest factor in longevity. You won't get very far overclocking, and lower voltage at the same time! You can safely run raised voltage (within reason), if you keep your temps in check! What kind of cooling are you going to use?

"Undervolting" your gpu's probably won't affect the longevity of the system very much, but I don't see how it couldn't affect your hash rate in a bad way.  The key to longevity when it comes to computer hardware is to keep it on.  Power cycles wear out cards, it's better for everything to stay on all the time.  I was gonna say just keep it cool, but you already plan to do that 

Anyone here undervolts their GPU's for prolonged longevity?

I would be interested in their experiences. I plan to overclock by not more than 10% with massive, massive cooling installed on my cards. The memory down to 300 MHz and the Voltage I am not sure about.