You have a higher chance of winning the silicon lottery with a Core i9 13900KF than the 13900K

Intel Raptor Lake processor overclocking with liquid nitrogen in Israel labs.
(Image credit: Intel)
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A massive effort to test and sort Intel Raptor Lake CPUs by their overclocking ability has led to some surprising results. Igor's Lab, with the help of MIFCOM, has tested over 500 of Intel's latest (opens in new tab) 13th Gen processors to find out whether they're overclocking naturals or silicon saps. From this data, it's drawn the conclusion that, surprisingly, the Core i9 13900KF might be one of the best overclockers this generation. Even beating the pricier Core i9 13900K (opens in new tab).

The incredibly complex lithographic process that etches immensely complex designs onto silicon is extremely accurate nowadays, but it's still not perfect. Minuscule differences between individual dies can see one CPU performing better than another when it comes to overclocking. In short, some CPUs are simply made better than others. 

Admittedly, the days of near-perfect CPUs running hundreds, if not thousands, of megahertz faster than another of the same model are long gone. But there are still so-called 'golden samples'—CPUs that take to overclocking better than others. Whether you get one is largely based on luck of the draw, though you can play the odds in your favour, as Igor's Lab reports (via Tom's Hardware (opens in new tab)).

The first batch of test results to be posted compares the Core i9 13900K and the Core i9 13900KF—the latter being the slightly stripped back variant of the Core i9 13900K without any onboard graphics (iGPU). The results compare these two chips using Asus's own Silicon Prediction (SP) function on its motherboards. This is essentially a rating of any given chip's overclocking potential, largely based on a voltage curve set for each CPU at the factory.

The higher the SP value, the better a chip's overclocking potential.

The results from the large batch test are pretty surprising. The iGPU-less Core i9 13900KF is generally more likely to have a higher combined SP value (both P-core and E-core values combined) than the more expensive Core i9 13900K, at 101.1 to 99.6, respectively.

This isn't the result I was expecting, but I suppose it does make sense why this might be the case. Intel is binning its CPUs to ensure that the best dies go into the most expensive chips, but perhaps what we're seeing here is the product of removing the iGPU from the equation.

Inside Intel's Fab 28.

Intel's Fab 28 facility. (Image credit: Intel)

Take, for example, a Raptor Lake CPU die fresh off the wafer at Intel's fab facility in Israel (opens in new tab). The max configuration for Raptor Lake is in an 8+16 (P-cores and E-cores), which means only the perfectly functional dies end up in the Core i9 13900K. If some E-cores don't function on the die, it's destined for a Core i7 or below processor. If some P-cores aren't working, it's likely headed to a Core i5 or below. If all is working well, it's likely going to be stuck into a Core i9. 

Yet for the Core i9 13900K, Intel also needs a fully functional iGPU on board. Without that working as intended, the die ends up in the Core i9 13900KF. You could have a wildly impressive CPU component on a die yet no working GPU and it'll end up in the Core i9 13900KF.

The other thing to consider is that the absolutely best Raptor Lake dies, the ones with all the cores working and a functioning GPU, will be binned not only for the Core i9 13900K but also the recently released Core i9 13900KS (opens in new tab). That chip hasn't been factored into these results as it only just launched last week, but effectively the Core i9 13900KS is made up of the best dies out of the Raptor Lake production line. 

Essentially, Intel's skimming the best dies off the top of the Core i9 13900K stack for the Core i9 13900KS. It's that binning process that you're paying an extra $100 for.

That could be again why we see the Core i9 13900KF end up with higher SP scores, and thus the likelihood of better overclocking potential. The Core i9 13900KF is the end of the road for some CPU dies, whereas the Core i9 13900K is not.

Trays of 12th or 13th Gen Intel processors waiting to be tested.

(Image credit: Intel)

In the second wave of results (opens in new tab), Igor's Lab compares the Core i7 13700K and Core i7 13700KF, and the Core i5 13600K and Core i5 13600KF.

And again, there's a lot going on to talk about.

For starters, the Core i7 13700K actually has a lower average SP value at 82.9 than the Core i7 13700KF at 83.5. However, the K-series chip data shows a much wider spread of performance, both above and below the average value. A handful of chips show a value above 90, while many sit below 80.

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The Core i7 13700KF is far more likely to have a middling SP value. Not a single chip tested offered an SP value above 90, and by far the most common value was 86. There were fewer lower scoring chips too. 

Where things get even more interesting is the Core i5 13600K (the best gaming CPU (opens in new tab), in our opinion) versus the Core i5 13600KF. Here the exact reverse is true; the Core i5 13600K has a higher average SP value at 81.8 and there's less variance in scores chip-to-chip. The Core i5 13600KF has, on average, an SP value of 78.5. However, some golden samples offered individual SP values much higher than the best Core i5 13600K samples, and some scores far lower, too.

Overclocking is not as massively impactful to real-world performance as it once was, and it's unlikely that a couple of SP points will net you any gain on your PC. But for the diehard hobbyist overclocker, it's not often you get so much data as this. Which CPU stands a better chance of winning the so-called silicon lottery is often based on anecdotal reports from other overclockers. To get this much data, which more or less lays out the best way to win the silicon lottery, is a great glimpse into how the binning process at Intel functions to separate out a generation's worth of processor dies.

Jacob Ridley
Senior Hardware Editor

Jacob earned his first byline writing for his own tech blog from his hometown in Wales in 2017. From there, he graduated to professionally breaking things as hardware writer at PCGamesN, where he would later win command of the kit cupboard as hardware editor. Nowadays, as senior hardware editor at PC Gamer, he spends his days reporting on the latest developments in the technology and gaming industry. When he's not writing about GPUs and CPUs, however, you'll find him trying to get as far away from the modern world as possible by wild camping.