Intel i9-12900K vs Ryzen 9 5900X

Intel i9-12900K and Ryzen 9 5900X are two processors that are used to build your own PC. We look at the critical factors that differentiate Ryzen 9 5900X from an Intel i9-12900K computer. Both processors are apt for gaming enthusiasts and allow overclocking on the processor.

CPU speed and L2, L3 Cache – i9-12900K vs Ryzen 9 5900X

In terms of processor speed and cache, i9-12900K and Ryzen 9 5900X have significant differences. We list these differences in a sequence.

  • i9-12900K has total 16 cores. 8 are efficient cores and the remaining 8 are performance cores. Ryzen 9 5900X has 12 cores in all.
  • The base frequency of i9-12900K is 2.40 GHz for the efficient cores and 3.20 GHz for the performance cores. Ryzen 9 5900X has a base frequency of 3.70 GHz.
  • The turbo frequency of the clock on Intel i9-12900K is 3.90 GHz for efficient cores and 5.10 GHz for performance cores. The Ryzen 9 5900X has a max turbo frequency up to 4.8 GHz.
  • i9-12900K has an L2 cache of 14 MB and an L3 cache of 30 MB. The Ryzen 9 5900X has an L2 cache of 6 MB and an L3 cache of 64 MB.

You would have noticed that the i9-12900K processors have a higher frequency than the Ryzen 9 5900X. However, the L3 cache of 64 MB outranks the L3 cache of i9-12900K by quite a distance.

PCIe 5 – Ryzen 9 5900X vs Intel i9-12900K

Intel i-12900K is compliant with the PCIe 5 standards. This allows the processor to peripheral communication and data transmission fast. PCI 5 is the double speed of the PCI 4 standards of data transmission. It can also work on PCIe 4 motherboards. The PCIe 5 standard allows 20 PCI lanes for the i9-12900K processors. Each lane can give a speed of up to GTs. All 20 lanes can give bandwidth speed on the PCI lanes up to 76.8 GTs.

Ryzen 9 5900X is compatible with PCI 4 standards. No PCI 5 support on the Ryzen 9 5900X processors.

Memory types – Intel i9-12900K vs Ryzen 9 5900X

Ryzen 9 5900X has a dependency on the type of RAM used. The speed of RAM can go up to 3200 MHz on a Ryzen 9 5900X based computer. If you deployed a higher frequency RAM, it will be forced to work at the 3200 MHz speed. Ryzen 9 5900X is not compatible with DDR5 RAM. It can work with DDR 4 RAM only.

Ryzen 9 5900X can support 64 GB maximum memory capacity.

Intel i9-12900K, however, can work with DDR 5 and DDR 4 RAM. DDR 5 RAM allows you to work at 4800 MTs, which is 50 percent higher than the speed of DDR 4 RAM at 3200 MTs. i9-12900K is more progressive in terms of the support for DDR 5 RAM types.

i9-12900K can support maximum memory of 128 GB in the two slots on the motherboard. Each slot can carry 2 DIMMs though.

T-Junction on Intel i9-12900K vs Ryzen 9 5900X

The maximum temperature or the T-Junction value for i9-12900K is 100 degrees, whereas the Ryzen 9 5900X has a T-Junction value of 90 degrees. Should you choose to overclock your AMD Processor, you will need to watch out for overheating of the processor. If you are unaware, AMD has clearly stated warranty terms. If you overclock the processor, the warranty on the processor will cease to exist.

Integrated graphics – i9-12900K vs Ryzen 9 5900X

i9-12900K comes with integrated graphics with a base frequency of 300 MHz. The maximum frequency can go up to 1.55 GHz. Ryzen 9 5900X does not have integrated graphics. You will need to get an external display adapter for the display configuration of your custom new PC. Ryzen 9 5900X is just like the Intel i9-12900KF. The i9-12900KF processor does not have integrated graphics and you will need to buy a new display adapter for the display capabilities on the Intel i9-12900KF.

Windows 11 – i9-12900K vs Ryzen 9 5900X

Both processors, i9-12900K and Ryzen 9 5900X are compatible with Windows 11. AMD has tested the Ryzen 9 5900X and has claimed performance metrics on a Windows 10 based computer. However, you can check Microsoft’s list of processors that are compatible with Windows 11. It does contain the Intel i9-12900K and Ryzen 9 5900X processors for Windows 11 compatibility.

There are chances that you may get Windows 10 on your new custom PC. This should get updated to Windows 11 as part of the Windows Update program on your computer. A natural update from Windows 10 to Windows 11 should do the trick for your cause on Intel i9-12900K and the Ryzen 9 5900X based computers.

Benchmarks – Intel i9-12900K vs Ryzen 9 5900X

The benchmark scores for Intel i9-12900K and the Ryzen 9 5900X are mentioned below for your ready reference:

  • Geekbench score for single i9-12900K processor is 1999 and for all the cores, the score is 17205 for all the 16 cores. Ryzen 9 5900X has a geekbench score of 14023 for all 12 cores of the processor and 1671 for the single processor.

If you were to base your decision on the Benchmark scores, the performance of i9-12900K is at least 20 percent higher than the Ryzen 9 5900X processor.


Between i9-12900K and Ryzen 9 5900X, I would choose an Intel i9-12900K for the following reasons:

  • better processor speed
  • PCIe 5 compatibility
  • DDR 5 RAM compatibility
  • Integrated graphics

In terms of costs, the Ryzen 9 5900X is cheaper by almost $100. But, you will need to factor in the costs of an external display adapter to get the display working. It would average out, eventually. Therefore, we feel that the i9-12900K offers you the maximum value for top-end gaming enthusiasts. If you are still keen on getting a Ryzen, then choose the Ryzen 6000 series processors to take care of the bottlenecks of the Ryzen 9 5900X processor.

You may also like to read more about Intel processors in the following pages:

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Rajesh Dhawan

Rajesh Dhawan is a technology professional who loves to blog about smart wearables, Cloud computing and Microsoft technologies. He loves to break complex problems into manageable chunks of meaningful information.