Intel Core i9-13900K vs Intel Core Ultra 7 255HX Comparison

The Intel Core Ultra 7 255HX and the Intel Core i9-13900K represent two distinct philosophies in processor design: one is a modern, power-efficient mobile chip built on a state-of-the-art process, while the other is a high-power desktop flagship from a previous generation. The benchmark data reveals a clear split, with the desktop i9 dominating most heavy multi-threaded workloads, but the mobile Ultra 7 showing surprising strength in specific math and single-core tests. This analysis breaks down the head-to-head results, architecture, and use cases based solely on the provided facts.

Head-to-Head Benchmarks

The most striking pattern in the head-to-head data is the sheer number of wins for the Intel Core i9-13900K. Out of 17 benchmark comparisons, the i9-13900K takes 14 victories, while the Core Ultra 7 255HX manages only 3. This dominance is most pronounced in multi-threaded and memory-intensive tasks. For instance, in Cinebench R23 multi-core, the i9-13900K scores 38271.5 against the Ultra 7's 32612, a lead of 14.8%. The gap widens further in PassMark's integer math test, where the i9-13900K's score of 207792 is a massive 38.8% higher than the Ultra 7's 127126. Data compression shows an even larger disparity, with the i9-13900K scoring 793645 compared to 515143, a 35.1% advantage for the desktop chip.

The i9-13900K's lead extends to other multi-core workloads, though the margins vary. In Cinebench R20 multi-core, it leads by 17.1% (20740 vs 17187), and in PassMark's multithread test, it is ahead by 17.7% (58589 vs 48234). Even in single-threaded tests, the i9-13900K generally holds the edge, albeit a smaller one. In Cinebench R23 single-core, it wins by a modest 3.4% (2238.5 vs 2163), and in PassMark single-thread, it is only 1% ahead (4608 vs 4562). The i9-13900K also wins in extended instructions (46477 vs 41247, an 11.3% gap), random string sorting (87705 vs 62591, a 28.6% gap), and data encryption (46609 vs 39499, a 15.3% gap).

However, the Core Ultra 7 255HX has its moments of triumph. Its most significant victory is in PassMark's find prime numbers test, where it scores 400 against the i9-13900K's 236. This represents a staggering 69.5% advantage for the Ultra 7. It also wins in floating point math, scoring 160624 versus 151562, a 6% lead. In Cinebench R15 single-core, the Ultra 7 edges out a win with a score of 327 versus 318, a 2.8% difference. These wins suggest the Arrow Lake architecture has specific strengths in certain mathematical operations, even if it cannot match the raw throughput of the Raptor Lake chip in most other areas.

Architecture Differences

The two processors are built on fundamentally different foundations. The Core Ultra 7 255HX uses the Arrow Lake architecture, specifically the Arrow Lake-HX codename, and is manufactured on a 3 nm process node by TSMC. In contrast, the Core i9-13900K uses the Raptor Lake architecture (Raptor Lake-S codename) and is built on a 10 nm process node by Intel. This process advantage is significant, as the 3 nm node allows for much denser transistors; the Ultra 7 packs 17,800 million transistors into a 243 mm² die, while the i9-13900K's transistor count is not listed, but its die size is slightly larger at 257 mm².

Core configuration also differs substantially. The Ultra 7 255HX has 20 cores and 20 threads, indicating it lacks hyper-threading. The i9-13900K, on the other hand, has 24 cores and 32 threads, meaning it does use hyper-threading. This core and thread disparity is a primary reason for the i9-13900K's dominance in multi-threaded benchmarks. Cache hierarchies are also different: the Ultra 7 has a larger per-core L1 cache (192 KB) and L2 cache (3 MB), but a smaller shared L3 cache (30 MB) compared to the i9-13900K's 80 KB L1, 2 MB L2, and 36 MB L3. The i9-13900K also supports both DDR4 and DDR5 memory, while the Ultra 7 is limited to DDR5.

Other architectural differences include the integrated graphics. The Ultra 7 255HX features Arc Xe-LPG Graphics with 64 execution units, while the i9-13900K has the older UHD Graphics 770. The mobile chip also has more PCIe lanes (20 vs 16, both Gen 5). The Ultra 7 is a mobile part on the Intel BGA 2114 socket, while the i9-13900K is a desktop part on the Intel Socket 1700. The Ultra 7's base clock is 2.40 GHz with a boost of 5.20 GHz, while the i9-13900K has a higher base clock of 3.00 GHz and a boost of 5.80 GHz.

Where Each One Wins

The benchmark results paint a clear picture of which workloads favor which processor. The Intel Core i9-13900K is the clear winner for any task that scales with core count and raw throughput. Its 24 cores and 32 threads give it a decisive advantage in video rendering (Cinebench R23 multi-core), code compilation, and data compression. The 38.8% lead in integer math and the 35.1% lead in data compression make it the superior choice for productivity applications that rely on these operations. For users running heavy multi-threaded desktop workloads, the i9-13900K is the stronger performer based on the data.

The Intel Core Ultra 7 255HX, despite being a mobile chip with fewer threads, wins in specific niches. Its 69.5% advantage in the find prime numbers test suggests it has a particularly efficient integer unit for certain algorithms. Its 6% win in floating point math is also notable, indicating that the Arrow Lake architecture handles these calculations well. The single-core win in Cinebench R15 (2.8% ahead) shows that the Ultra 7 can compete with, and even beat, the i9-13900K in lightly threaded legacy workloads. This makes it a viable option for users who prioritize single-threaded performance in older applications or who need a mobile platform with strong floating-point capabilities.

Specification Differences

The specification sheets reveal several key differences beyond the core and cache configurations. The most obvious is the TDP: the Ultra 7 255HX has a 55W TDP, while the i9-13900K has a 125W TDP. This points to the Ultra 7 being designed for power efficiency in laptops, whereas the i9-13900K is a high-power desktop part. The memory support differs, with the i9-13900K supporting both DDR4 and DDR5, while the Ultra 7 only supports DDR5. The i9-13900K also supports ECC memory, while the Ultra 7 does not. The memory bandwidth for the Ultra 7 is listed at 102.4 GB/s, while no figure is provided for the i9-13900K.

The market segments are fundamentally different: the Ultra 7 is a mobile processor, and the i9-13900K is a desktop processor. Their release dates are also different, with the i9-13900K launching on 2022-09-26 and the Ultra 7 on 2025-01-12. Both have unlocked multipliers, but they use different sockets (BGA 2114 vs Socket 1700) and have different part numbers (SRVFG vs SRMBH). The i9-13900K has a launch MSRP of $589; the Ultra 7 has no listed launch MSRP. Both are currently listed as active in production.

FAQ

Q: Which processor is faster in multi-core Cinebench R23?

A: The Intel Core i9-13900K is faster, scoring 38271.5 compared to the Intel Core Ultra 7 255HX's 32612, a 14.8% difference.

Q: Does the Intel Core Ultra 7 255HX win any benchmark by a significant margin?

A: Yes, it wins the PassMark find prime numbers test with a score of 400, which is 69.5% higher than the Intel Core i9-13900K's score of 236.

Q: What is the difference in core and thread counts?

A: The Intel Core Ultra 7 255HX has 20 cores and 20 threads, while the Intel Core i9-13900K has 24 cores and 32 threads.

Q: Which processor supports ECC memory?

A: The Intel Core i9-13900K supports ECC memory, while the Intel Core Ultra 7 255HX does not.

Q: How do the single-threaded PassMark scores compare?

A: They are very close. The Intel Core i9-13900K scores 4608, and the Intel Core Ultra 7 255HX scores 4562, a difference of only 1%.

Q: What are the process nodes for each processor?

A: The Intel Core Ultra 7 255HX is built on a 3 nm process by TSMC, while the Intel Core i9-13900K is built on a 10 nm process by Intel.

The Verdict

The data clearly indicates that the Intel Core i9-13900K is the superior processor for raw performance in most scenarios. Its 14 wins out of 17 benchmarks, particularly its massive leads in multi-threaded tasks like data compression (35.1%), integer math (38.8%), and Cinebench R23 multi-core (14.8%), make it the obvious choice for a desktop workstation or high-end gaming PC where maximum throughput is required. Its higher boost clock of 5.80 GHz and support for both DDR4 and DDR5 also give it flexibility.

The Intel Core Ultra 7 255HX, however, is not without merit. Its 69.5% win in the find prime numbers test and 6% win in floating point math suggest it has a specialized, efficient architecture for certain calculations. Its 55W TDP makes it suitable for mobile devices where power consumption is a concern. For a laptop user who needs strong floating-point performance or runs specific algorithms that favor its design, the Ultra 7 is a capable choice. However, for a desktop user prioritizing maximum multi-threaded performance, the i9-13900K is the clear winner based on all the benchmark data provided.