Intel Core i9-10900K vs Intel Core Ultra 5 125H Comparison

The Verdict

The data presents a clear split: the Intel Core Ultra 5 125H is a mobile processor that wins on efficiency-oriented and encryption workloads, while the Intel Core i9-10900K is a desktop part that dominates sustained multi-threaded and single-threaded performance. The i9-10900K takes 11 of the 17 head-to-head benchmark wins, while the Ultra 5 125H claims 6. However, the Ultra 5 125H matches the i9-10900K in overall percentile ranking, with both sitting at the 79th percentile of all CPUs. The average benchmark scores are close—27,507 for the Ultra 5 versus 27,872 for the i9—but the distribution of wins is lopsided. The i9-10900K is the pick for heavy compute tasks like video rendering, data compression, and extended instruction workloads. The Ultra 5 125H is the pick for encryption, prime number finding, and physics simulations, plus it offers a newer architecture and integrated Arc graphics. The i9-10900K carries a higher launch MSRP of $547 versus $375 for the Ultra 5 125H, but pricing considerations are not part of this analysis.

Architecture Differences

The two processors come from completely different design eras. The Intel Core Ultra 5 125H is built on a 7 nm process and uses the Meteor Lake architecture, while the Intel Core i9-10900K uses the older 14 nm process with the Comet Lake architecture. The Ultra 5 125H packs 14 cores and 18 threads, whereas the i9-10900K has 10 cores and 20 threads. The core count advantage goes to the Ultra 5, but the thread count advantage goes to the i9-10900K.

Cache configurations differ significantly. The Ultra 5 125H has 112 KB of L1 cache per core and 2 MB of L2 cache per core, with 18 MB of shared L3 cache. The i9-10900K has 64 KB of L1 per core, 256 KB of L2 per core, and 20 MB of shared L3 cache. The i9-10900K has more total L3 cache, but the Ultra 5 benefits from larger per-core L1 and L2 allocations.

Memory support is a major differentiator. The Ultra 5 125H supports DDR5 memory with a dual-channel bus and a memory bandwidth of 89.6 GB/s. The i9-10900K supports DDR4 memory, also dual-channel, but with a much lower memory bandwidth of 46.9 GB/s. The Ultra 5 also features PCIe Gen 5, while the i9-10900K is limited to PCIe Gen 3 with 16 lanes from the CPU.

The integrated graphics tell a generational story. The Ultra 5 125H has Arc Xe-LPG with 96 execution units, while the i9-10900K has the older UHD Graphics 630. The Ultra 5 125H is a mobile part with a 28 W TDP, socketed in Intel BGA 2049, and is still in active production. The i9-10900K is a desktop part with a 125 W TDP, socketed in Intel Socket 1200, and is end-of-life. The i9-10900K has an unlocked multiplier, while the Ultra 5 does not. The i9-10900K has a larger die size at 206 mm², though the Ultra 5's die size is not listed.

Where Each One Wins

The benchmark wins are concentrated in distinct workload categories. The Intel Core i9-10900K wins decisively in multi-core rendering. In Cinebench R23 multi-core, it scores 18,895 against the Ultra 5's 12,804.5, a 32.2% advantage. The i9-10900K also wins in Cinebench R20 multi-core with 7,935 versus 7,161, and in Cinebench R15 multi-core the Ultra 5 actually takes the win with 2,021.5 versus 1,904, a 6.2% edge. Single-core performance is entirely in the i9-10900K's favor: Cinebench R23 single-core shows 2,667 versus 1,647.5, a 38.2% gap, and Cinebench R20 single-core shows 1,120 versus 1,010, a 9.8% gap.

The i9-10900K dominates in data compression, scoring 375,336 against the Ultra 5's 236,209, a 37.1% lead. It also wins in extended instructions (24,620 versus 13,749, a 44.2% lead), integer math (85,404 versus 69,986, an 18.1% lead), random string sorting (46,389 versus 27,435, a 40.9% lead), and floating-point math (53,123 versus 51,670, a 2.7% lead). The i9-10900K also wins PassMark multithread with 22,452 versus 21,100, a 6% edge.

The Ultra 5 125H wins where the newer architecture shines. Its data encryption score of 14,251 crushes the i9-10900K's 7,796, an 82.8% advantage. It also wins in find prime numbers (88 versus 63, a 39.7% lead) and physics simulation (1,439 versus 1,029, a 39.8% lead). The Ultra 5 125H takes the PassMark single-thread test with 3,399 versus 3,113, a 9.2% win. The i9-10900K wins the Cinebench single-core tests despite losing PassMark single-thread—a workload-dependent split.

FAQ

Q: Which processor has better multi-core rendering performance?

A: The Intel Core i9-10900K wins in Cinebench R23 multi-core with 18,895 versus 12,804.5, a 32.2% lead. It also wins Cinebench R20 multi-core with 7,935 versus 7,161. However, the Ultra 5 125H wins Cinebench R15 multi-core with 2,021.5 versus 1,904, a 6.2% edge.

Q: Is the Ultra 5 125H faster in single-core workloads?

A: It depends on the benchmark. The Ultra 5 125H wins PassMark single-thread with 3,399 versus 3,113, a 9.2% lead. But the i9-10900K wins Cinebench R23 single-core with 2,667 versus 1,647.5 and Cinebench R20 single-core with 1,120 versus 1,010.

Q: Which processor has better memory bandwidth?

A: The Ultra 5 125H supports DDR5 memory with a bandwidth of 89.6 GB/s, while the i9-10900K supports DDR4 with a bandwidth of 46.9 GB/s. The Ultra 5's memory bandwidth is nearly double.

Q: How do the core counts compare?

A: The Ultra 5 125H has 14 cores and 18 threads, while the i9-10900K has 10 cores and 20 threads. The Ultra 5 has more physical cores, but the i9-10900K has more threads due to its hyper-threading implementation.

Q: What is the production status of each processor?

A: The Ultra 5 125H is active in production, while the i9-10900K is end-of-life. The Ultra 5 was released on December 13, 2023, and the i9-10900K was released on April 29, 2020.

Q: Which processor has a higher overall benchmark average?

A: The i9-10900K has an average benchmark score of 27,872, while the Ultra 5 125H has an average of 27,507. Both sit at the 79th percentile of all CPUs. The i9-10900K's nearest rival is the AMD Ryzen 7 6800U at 27,887, while the Ultra 5's nearest rival is the AMD Ryzen 7 5800 at 27,535.

Head-to-Head Benchmarks

The biggest win for the Ultra 5 125H is in data encryption, where it scores 14,251 against the i9-10900K's 7,796, an 82.8% advantage. This is the largest delta in either direction across all head-to-head tests. The second-largest Ultra 5 win is in physics simulation, with 1,439 versus 1,029, a 39.8% lead. The find prime numbers test also goes to the Ultra 5, with 88 versus 63, a 39.7% advantage. The Ultra 5 additionally wins PassMark single-thread with 3,399 versus 3,113, a 9.2% lead, and Cinebench R15 multi-core with 2,021.5 versus 1,904, a 6.2% edge.

The i9-10900K's biggest win is in Cinebench R23 single-core, where it scores 2,667 versus 1,647.5, a 38.2% lead. Its second-largest win is in extended instructions, with 24,620 versus 13,749, a 44.2% advantage. The i9-10900K also dominates random string sorting with 46,389 versus 27,435, a 40.9% lead, and data compression with 375,336 versus 236,209, a 37.1% edge. In Cinebench R23 multi-core, the i9-10900K scores 18,895 versus 12,804.5, a 32.2% lead. Integer math goes to the i9-10900K with 85,404 versus 69,986, an 18.1% margin.

The remaining wins are narrower. The i9-10900K takes Cinebench R20 multi-core with 7,935 versus 7,161, a 9.8% lead, and Cinebench R20 single-core with 1,120 versus 1,010, also a 9.8% lead. PassMark multithread goes to the i9-10900K with 22,452 versus 21,100, a 6% edge. Floating-point math is the closest contest, with the i9-10900K winning 53,123 versus 51,670, a 2.7% margin. Cinebench R15 single-core goes to the i9-10900K with 268 versus 241, a 10.1% lead. The i9-10900K also wins PassMark data compression, extended instructions, integer math, and random string sorting by substantial margins, confirming its strength in compute-heavy desktop workloads. The Ultra 5 125H counters with wins in encryption, physics, prime finding, and single-thread PassMark, showing that its newer Meteor Lake architecture brings specific advantages despite the older i9's raw power.