A $20 Multimeter Might Reveal Your CPU's Overclocking Potential

Can you predict how well your CPU will overclock by probing it with a multimeter? Before you start pulling out the Fluke, let's go over the details of this story, because it's both more and less interesting than you might expect from the headline. The short version is that retro tech YouTuber Bits und Bolts has been overclocking a whole lot of Socket 370 CPUs, and he's found a startling connection between the internal resistance of Pentium III processors and how well they overclock.

Specifically, what he found was that, within a specific stepping, processors with lower resistance between the VCC and Ground pins on the CPU typically achieve higher clock rates with less voltage when overclocked. "More MHz, fewer millivolts" is exactly what you want when overclocking, so if the correlation holds up, this is actually quite the discovery, at least for retro overclockers. So does it hold up?


Actually, yeah, mostly. There are a few caveats; he has at least one processor (out of dozens) that doesn't fit the pattern, and you can only compare resistance between processors of the same model (i.e. Celeron vs. Celeron) and on the same stepping; an A1 processor with higher resistance might still be a better overclocker than a B1 processor with lower resistance because it's relatively better for that stepping. He also found that processors which were binned higher by Intel typically had lower resistance, which supports the theory.


Does any of this apply to processors made in this decade? Probably not, for a few reasons. For one, modern processors are enormously more complicated internally; there are many parallel paths for power to take, and the internal voltage regulation circuitry is incredibly complex. Attempting to measure this on a current chip will give you a resistance value low enough that the resistance of your probes and the LGA pads starts to become a concern. And while the minuscule power levels used for resistance testing aren't going to damage your processor, you could easily short two pads or even damage a pad just enough to ruin its conductivity, destroying the CPU.


So saying, probably don't try this at home on modern chips. But if you have old Socket 370 hardware, especially if it's from the Tualatin generation, Bits und Bolts would love to see your data. Pull the CPU, whip out your multimeter, and generate some data; then, go post it in his comment section under the video above.


And if for some reason you don't have a digital multimeter, it's the most important tool in any electronics tech's arsenal. You can pick one up today for just $20, and you'll surprise yourself with how useful it can actually be for all kinds of handyman and repair jobs. Either of the ones linked above is good enough to get you started.