Intel Core i9-12900K vs Intel Core Ultra X7 358H Comparison

Where Each One Wins

The benchmark split is decisive but not one-sided. The Intel Core i9-12900K wins 13 of the 17 head-to-head comparisons, while the Intel Core Ultra X7 358H takes 4. The i9-12900K dominates in heavily threaded productivity workloads, particularly rendering and compression. Its largest victories come in integer math, data compression, and Cinebench multi-core tests, where the delta reaches as high as 67.3%. This is a desktop part built for sustained throughput, and the data reflects that.

The Core Ultra X7 358H, by contrast, wins in a narrower set of tests that favor efficiency and certain instruction patterns. It takes Cinebench R15 single-core by 4.1%, Cinebench R23 single-core by 3.6%, PassMark find prime numbers by 56.4%, and PassMark physics by 26.5%. These are not trivial wins. The prime number test, in particular, shows a workload where the mobile part's architecture provides a massive advantage. The physics score also indicates that the Ultra X7 handles simulation-style calculations much better than the older desktop chip.

For general use, the single-threaded scores are nearly identical. The i9-12900K edges out the Ultra X7 in PassMark single-thread by 0.3%, a margin that is effectively noise. The real story is multi-threaded performance, where the i9-12900K's 24 threads versus the Ultra X7's 16 threads creates a massive gulf in parallel workloads. If the task scales with cores and threads, the i9-12900K wins by a wide margin. If the task is single-threaded or relies on specific instruction-level efficiency, the Ultra X7 can be competitive or better.

Architecture Differences

The two processors come from very different Intel design eras. The i9-12900K is Alder Lake-S, built on Intel's 10 nm process, while the Ultra X7 358H is Panther Lake, built on Intel's 3 nm process. That process gap explains much of the efficiency difference. The i9-12900K has a TDP of 125 watts, while the Ultra X7 358H has a TDP of 25 watts, a five-fold reduction. The desktop part compensates with a boost clock of 5.20 GHz versus 4.80 GHz on the mobile chip.

Core counts are identical at 16, but thread counts differ sharply. The i9-12900K supports 24 threads, implying hyperthreading on its performance cores. The Ultra X7 358H supports only 16 threads, meaning it has 16 physical cores without hyperthreading or a hybrid arrangement that does not duplicate threads. Cache layouts also diverge. The i9-12900K has 80 KB L1 per core, 1.25 MB L2 per core, and 30 MB shared L3. The Ultra X7 358H has 192 KB L1 per core, 3 MB L2 per core, and 18 MB shared L3. The newer part has much larger per-core caches but a smaller shared pool.

Memory support is a major differentiator. The i9-12900K supports DDR4 and DDR5 with dual-channel access and a recorded bandwidth of 76.8 GB/s. The Ultra X7 358H supports LPDDR5X with dual-channel access and a recorded bandwidth of 153.6 GB/s, exactly double. The mobile chip also uses a different socket, Intel BGA 2540, and is not overclockable, while the i9-12900K sits in Intel Socket 1700 and has an unlocked multiplier.

The integrated graphics differ as well. The i9-12900K carries UHD Graphics 770, while the Ultra X7 358H carries Arc B390. The Ultra X7 also has fewer CPU PCIe lanes, Gen 5 with 4 lanes, compared to the i9-12900K's Gen 5 with 16 lanes. The desktop chip supports ECC memory, the mobile chip does not. The i9-12900K launched on November 3, 2021 with a launch MSRP of $599. The Ultra X7 358H launched on January 4, 2026. The i9-12900K has a die size of 215 mm², while the Ultra X7's die size is not recorded.

Head-to-Head Benchmarks

The largest win for either side belongs to the i9-12900K in PassMark integer math. It scores 139090 against 83147, a delta of 67.3%. That is the single biggest percentage gap in the entire comparison. Data compression is also lopsided: 537341 versus 332508, a 61.6% advantage for the desktop chip. Cinebench R23 multi-core shows a 39.4% gap, with the i9-12900K scoring 26125 against 18747. Cinebench R15 multi-core is close behind at 34%, with scores of 4057 and 3027. Random string sorting goes to the i9-12900K by 41.5%, and extended instructions by 23.5%.

The Ultra X7's wins are equally clear. PassMark find prime numbers is its standout: 337 versus 147, a delta of 56.4% in its favor. PassMark physics shows 3021 versus 2219, a 26.5% advantage. Cinebench R15 single-core is a narrow win at 301.5 versus 289, a 4.1% margin. Cinebench R23 single-core goes 2080 versus 2004.5, a 3.6% margin. These single-core wins are modest, but they are consistent across two Cinebench versions.

Several tests are close enough to be considered ties. PassMark floating point math is nearly even: 105471 versus 103842, only a 1.6% edge for the i9-12900K. PassMark single-thread is 4136 versus 4124, a 0.3% margin for the desktop part. The 3DMark tests appear only in the individual benchmark lists, not in the head-to-head set, so they do not factor into the win count. The i9-12900K's 3DMark scores are 1073 single-thread, 2120 for 2 threads, 4145 for 4 threads, 7596 for 8 threads, 9912 for 16 threads, and 11620 for max threads. The Ultra X7 has no recorded 3DMark scores in this data set.

Cinebench R20 multi-core goes to the i9-12900K at 14679 versus 12011, a 22.2% gap. Cinebench R20 single-core also goes to the i9-12900K at 2072 versus 1695, also a 22.2% gap. That is an unusual result, since the Ultra X7 wins the other two single-core Cinebench tests. PassMark multithread favors the i9-12900K at 41213 versus 33802, a 21.9% margin. Data encryption is closer, 29579 versus 26046, a 13.6% edge for the desktop chip.

The Verdict

The data paints a clear picture for two different buyers. The Intel Core i9-12900K is the choice for anyone running multi-threaded workloads that scale with core count and thread count. Its 24 threads, 5.20 GHz boost clock, and 30 MB shared L3 deliver 39.4% higher Cinebench R23 multi-core scores and 67.3% higher integer math scores than the Ultra X7. The desktop chip also wins in data compression by 61.6%, making it far better for file archiving, database operations, and content creation pipelines that use all available cores. The i9-12900K's 88th percentile ranking among all CPUs, with an average benchmark score of 42335, puts it just ahead of the AMD Ryzen 5 7400 and AMD Ryzen 9 PRO 8945HS, and essentially tied with the Intel Core i9-12950HX.

The Intel Core Ultra X7 358H is the choice for efficiency-constrained environments and specific single-threaded or instruction-sensitive tasks. Its 25 watt TDP, 153.6 GB/s memory bandwidth, and 3 nm process make it suitable for mobile systems where power draw matters. It wins in prime number finding by 56.4% and physics by 26.5%, suggesting an edge in certain scientific and simulation workloads. Its single-core Cinebench scores are also higher than the i9-12900K's in R15 and R23, though the PassMark single-thread test shows a 0.3% edge for the desktop part. The Ultra X7 sits at the 87th percentile with an average benchmark score of 40967, placing it near the AMD Ryzen AI 5 PRO 440 and Intel Core Ultra 7 356H.

The choice is not about which chip is better overall, it is about which workload matters more. For sustained multi-threaded rendering, compression, or math-heavy parallel tasks, the i9-12900K wins by margins that are impossible to ignore. For a thin-and-light laptop with long battery life, or for workloads that reward the Ultra X7's specific architecture strengths, the mobile chip is the right pick. The i9-12900K has 13 wins, the Ultra X7 has 4, but those 4 wins are in categories where the mobile chip is dramatically better. The data does not support declaring one a universal winner.

FAQ

Q: Which processor has more threads?

A: The Intel Core i9-12900K has 24 threads, while the Intel Core Ultra X7 358H has 16 threads. Both have 16 cores.

Q: How much faster is the i9-12900K in multi-core Cinebench R23?

A: The i9-12900K scores 26125 versus 18747 for the Ultra X7, a 39.4% advantage.

Q: Does the Ultra X7 win any benchmark by a large margin?

A: Yes, it wins PassMark find prime numbers by 56.4%, scoring 337 versus 147 for the i9-12900K.

Q: What is the memory bandwidth difference?

A: The Ultra X7 358H has 153.6 GB/s of memory bandwidth, which is double the i9-12900K's 76.8 GB/s.

Q: Which chip has a higher boost clock?

A: The i9-12900K boosts to 5.20 GHz, while the Ultra X7 358H boosts to 4.80 GHz.

Q: How do the average benchmark scores compare?

A: The i9-12900K has an average benchmark score of 42335, while the Ultra X7 358H has an average of 40967. The i9-12900K sits at the 88th percentile, the Ultra X7 at the 87th percentile.