15 specifications

Intel Core i9-9900K vs AMD Ryzen 7 3800X

On paper, the Intel Core i9-9900K boosts higher, and the AMD Ryzen 7 3800X carries more L3 cache. Specifications describe what each chip is designed to do; how much of that either one holds under continuous load is a separate question.

10 specifications · 3 with a higher side

Full specifications

Intel Core i9-9900K

Intel · Coffee Lake Refresh (9th gen) · Desktop

Full specifications

AMD Ryzen 7 3800X

AMD · Ryzen 3000 · Desktop

Cores and clocks

Cores

Threads

Base clock

3.6 GHz

3.9 GHz

Boost clock

5.0 GHz

4.5 GHz

Cache and power

L3 cache

16 MB

32 MB

TDP

95 W

105 W

Platform

Socket

FCLGA1151

AM4

Process

14 nm

7 nm

Integrated graphics

Intel UHD Graphics 630

Not verified

Launched

Not verified

2019-07-07

A check marks the higher figure only on rows where higher is unambiguously better. Rows without one are not ties; they are specifications where “better” has no meaning.

Reading the table

What the difference means.

Boost clock

The Core i9-9900K boosts to 5 GHz against 4.5 GHz, 11 percent higher. Across generations it is not a guide to speed on its own, for the reason above. Boost is also a peak: it is held for seconds to minutes, on one or two cores, while the cooling and the power limit allow. What either chip settles at under a long load is lower, and it depends on the cooler and the motherboard as much as the chip.

Cache

The Ryzen 7 3800X carries 32 MB of L3 cache against 16 MB. Cache is fast memory on the chip, and a larger one means the cores wait on main memory less often. Games, large spreadsheets and compiling respond to it; rendering and video export, which stream through data in order, respond much less.

Power and cooling

The Ryzen 7 3800X is rated at 105 W against 95 W. The rating is the heat the cooler has to move for the chip to hold its speed, and modern chips draw well above it in short bursts. A competent tower cooler suits the Ryzen 7 3800X; the Core i9-9900K is easier to keep quiet and fits smaller cases. A chip whose cooling falls short does not fail. It slows down, and it does so after the first minute, which is why short benchmarks miss it.

Platform

They use different sockets, FCLGA1151 and AM4, so moving from one to the other means a new motherboard. For an upgrade, that cost belongs in the comparison; for a new build, the newer platform is the one with later chips still to come.

Manufacturing process

The Ryzen 7 3800X is built on a 7 nm process against 14 nm. A finer process generally does the same work for less power. The names are marketing labels rather than measurements, though, and they are not comparable between manufacturers, so treat the row as a sign of how recent the design is and no more.

Which to pick, on paper

A quiet or compact build: Core i9-9900K; 95 W against 105 W: less heat to move, so a smaller cooler and slower fans.

What no table says

How much of its speed a processor keeps after the first minute depends on the cooling and the power limit of the machine it is in. If you own one of these, measure it: the test is free and runs in this browser.

Free CPU stress test

Questions

Is the Core i9-9900K better than the Ryzen 7 3800X?: By need, on the specifications: a quiet or compact build: the Core i9-9900K. No specification says how much speed either one keeps under a long load; that depends on the cooling and the power limit of the machine it is in, and it is what a sustained test measures.
Do the Core i9-9900K and the Ryzen 7 3800X use the same socket?: No. The Core i9-9900K uses FCLGA1151 and the Ryzen 7 3800X uses AM4, so switching means a new motherboard.
Which runs hotter, the Core i9-9900K or the Ryzen 7 3800X?: The Ryzen 7 3800X is rated at 105 W against 95 W, so it produces more heat under load and needs the larger cooler. How hot either one actually runs depends on the cooler and the case more than on the chip.

More comparisons

Every figure on this table is a design target. None of it is a measurement.

Nothing above describes how a processor behaves twenty minutes into a sustained workload, which is where two chips with nearly identical specifications routinely diverge. A boost clock is a ceiling the vendor permits, not a rate the chip sustains, and whether it holds depends on the cooling, the case, the power profile and the room. None of those appear on a specification sheet.

We deliberately do not reduce these figures to a single score. A composite invented from specifications would look authoritative and measure nothing, and choosing the weights would be choosing the winner.

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