Tag Archives: undervolting

Build your own Ethereum Mining Rig, part 4: Optimization

Same hardware: before (top) and after (bottom) GPU BIOS mods. Click to enlarge.

This fourth installment of our Ethereum mining guide will focus on optimizing your rig’s performance via GPU clock speed and voltage setting tweaks to achieve maximum efficiency.

The tweaks that I outline in this article are applicable whether you’re using Linux or Windows. If you’re using the hardware that was recommended in the first part of this guide (or very similar hardware), you should expect to achieve Ether mining performance gains of 20-25%, compared to stock settings! At the same time, you’ll reduce power consumption by 10-15% (and consequently, lower GPU temperature and fan noise).

More speed for less power—how is that possible? Click “read more” to find out, in our mining performance optimization guide!

Undervolting in Linux via modified video BIOS

Hex

Before VBE7: Creating custom vBIOS files meant manually editing hex and hoping for the best—yuck!

For a long time, I’ve held off on writing a guide about modifying your video BIOS for the purpose of lowering voltage. Undervolting has the potential to reduce power draw by about 50 watts per GPU, so it’s easy to understand the appeal—you’ll see a significant savings on your electricity bill if you’re running a 3×7950 rig (like the one in my guide) 24/7. Unfortunately, the AMD Radeon drivers in linux don’t allow voltage control, so the only current way to lower voltage below manufacturer-specified levels in linux is to modify your video card’s BIOS.

In the past, such a hack involved manually editing your vBIOS file by hand, using a hex editor. Most folks hesitate to make such a modification, as performing the edit can be tricky if you’re not familiar with hexadecimal—and a mistake can mean a bricked GPU. Due to the potential danger I had decided not to post a guide about manually modifying your vBIOS ROMs. After all, nobody wants to be left with a $300 paperweight after inadvertently trashing their video card.

Enter VBE7, a GUI-based vBIOS editor for Radeon 7xxx series GPUs. Now anyone can easily make changes to their vBIOS without having to muddle around in a hex editor, praying they get things right. I’ve been testing VBE7 for a few days now, and it appears to work brilliantly. Read on for my guide on creating your own custom power-saving vBIOS!