Ryzen 9 3900X vs i5-11400F

The Ryzen 9 3900X is about 5% faster at 1440p. Whether that is worth it depends on the rest of your build.

The gap changes with resolution.

CPU differences shrink as resolution rises — at 4K the graphics card does most of the work.

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.

So which should you buy?

The Ryzen 9 3900X is faster, but the i5-11400F is the better buy per dollar. Take the Ryzen 9 3900X only if you want the extra headroom and the price gap doesn't bother you.

Affiliate links — we earn a small commission on Amazon purchases at no cost to you, which keeps the calculator free. Full disclosure.

Common questions.

Straight answers on the Ryzen 9 3900X versus the i5-11400F.

• Is the Ryzen 9 3900X better than the i5-11400F?

  +

  Yes, but by less than the spec sheet suggests. At 1440p the Ryzen 9 3900X scores 66 against 63 for the i5-11400F — roughly 5% faster. It also costs about $342 more at MSRP, so the question is whether that gap is worth the money for your build.

• Does the Ryzen 9 3900X or i5-11400F bottleneck a RTX 3080?

  +

  Paired with a RTX 3080 at 1440p, the Ryzen 9 3900X build comes out 0% CPU-bound, and the i5-11400F build comes out 2% CPU-bound. Being GPU-bound is the healthy outcome — it means the graphics card is the part working hardest.

• Is it worth upgrading from the i5-11400F to the Ryzen 9 3900X?

  +

  Only if you are also lifting the rest of the build. The Ryzen 9 3900X is about 5% ahead at 1440p, and gaps like that shrink further at 4K where the GPU does more of the work. If you are upgrading from the i5-11400F purely for frames, check the pairing first.

• Which is better value, the Ryzen 9 3900X or the i5-11400F?

  +

  On performance per dollar at MSRP, the i5-11400F wins. The Ryzen 9 3900X lists at $499 for an index of 66, and the i5-11400F at $157 for 63.