The gap changes with resolution.
CPU differences shrink as resolution rises — at 4K the graphics card does most of the work.
| Resolution | i9-10900K | i3-12100F | Difference |
|---|---|---|---|
| 1080p | 72 | 72 | 0% |
| 1440p | 70 | 68 | +3% |
| 4K | 68 | 64 | +6% |
In a real build with a RTX 3080.
Specs alone don’t tell you which to buy. Here is what each one does when it’s actually paired up, at 1440p.
| Game (1440p, paired with the RTX 3080) | i9-10900K | i3-12100F |
|---|---|---|
| League of Legends | 293 fps | 290 fps |
| Counter-Strike 2 | 251 fps | 248 fps |
| Grand Theft Auto V | 127 fps | 125 fps |
| Elden Ring | 105 fps | 104 fps |
| Cyberpunk 2077 | 79 fps | 79 fps |
| Starfield | 79 fps | 78 fps |
Modelled from benchmark data, not measured for every pairing. Our published error rate is 21.6% mean absolute error.
So which should you buy?
Whichever is cheaper on the day. There is roughly 3% between them at 1440p, which you will not notice in a game.
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Common questions.
Straight answers on the i9-10900K versus the i3-12100F.
Is the i9-10900K better than the i3-12100F?
They are close enough to call a tie. At 1440p the i9-10900K scores 70 on our index against 68 for the i3-12100F — a gap of about 3%, which is inside the margin where you would not feel a difference while gaming. Buy whichever is cheaper or easier to find.
Does the i9-10900K or i3-12100F bottleneck a RTX 3080?
Paired with a RTX 3080 at 1440p, the i9-10900K build comes out balanced, and the i3-12100F build comes out balanced. Being GPU-bound is the healthy outcome — it means the graphics card is the part working hardest.
Is it worth upgrading from the i3-12100F to the i9-10900K?
No. A 3% index gap will not be visible in games, and the money is better spent on the other side of the build — usually the GPU.
Which is better value, the i9-10900K or the i3-12100F?
On performance per dollar at MSRP, the i3-12100F wins. The i9-10900K lists at $547 for an index of 70, and the i3-12100F at $97 for 68.
Check either one against your build.
Pick a CPU and its counterpart, and get a verdict at all three resolutions in under 30 seconds.