Intel Core Ultra 7 255HX vs Intel Xeon 636 Comparison

The Intel Xeon 636 and Intel Core Ultra 7 255HX represent two distinct philosophies: a workstation-focused Granite Rapids chip with 12 cores and 24 threads, and a mobile Arrow Lake-HX processor with 20 cores and 20 threads. The benchmark data reveals a surprisingly close overall contest, with the Xeon 636 averaging 61,360 points across all tests and the Core Ultra 7 255HX averaging 62,738 points. The Ultra 7 edges ahead in the overall average, but the Xeon 636 counters with decisive wins in several key single-core and multi-core workloads, making the choice heavily dependent on specific application demands.

Head-to-Head Benchmarks

The most dramatic result in this comparison is in Cinebench R23 single-core, where the Xeon 636 scores 5,330 points against the Ultra 7 255HX's 2,163 points, a staggering 146.4% advantage. Similarly, in Cinebench R15 single-core, the Xeon 636 leads with 537 points versus 327 points, a 64.2% margin. These results are counterintuitive given the Ultra 7's higher 5.20 GHz boost clock, but the data is unambiguous: for single-threaded rendering tasks, the Xeon 636 is in a different league.

The multi-core picture is more balanced. The Ultra 7 255HX wins Cinebench R15 multi-core with 4,916 points versus 3,805 points (a 22.6% lead) and Cinebench R20 multi-core with 17,187 points versus 15,857 points (a 7.7% lead). However, the Xeon 636 strikes back in Cinebench R23 multi-core, scoring 37,757 points against the Ultra 7's 32,612 points, a 15.8% advantage. This suggests the Xeon 636 scales better in longer, more sustained rendering workloads, while the Ultra 7 excels in shorter bursts.

In PassMark tests, the split continues. The Xeon 636 wins integer math (138,281 vs. 127,126, an 8.8% lead), data compression (550,395 vs. 515,143, a 6.8% lead), extended instructions (43,282 vs. 41,247, a 4.9% lead), and physics (3,645 vs. 2,926, a 24.6% lead). The Ultra 7 255HX dominates floating-point math (160,624 vs. 107,826, a 32.9% lead), data encryption (39,499 vs. 27,193, a 31.2% lead), find prime numbers (400 vs. 255, a 36.2% lead), and random string sorting (62,591 vs. 54,420, a 13.1% lead). The Ultra 7 also takes PassMark single-thread (4,562 vs. 3,937, a 13.7% lead) and multithread (48,234 vs. 44,421, a 7.9% lead).

Overall, the Ultra 7 255HX wins 10 of the 17 head-to-head benchmarks, while the Xeon 636 takes 7. The Xeon's wins are often by larger margins, particularly in single-core Cinebench tests, while the Ultra 7's wins are more frequent but sometimes narrower. The PassMark multithread score, a composite metric, favors the Ultra 7 at 48,234 versus 44,421, indicating a broader multi-threaded advantage outside of Cinebench R23 specifically.

The Verdict

The data supports a clear split: the Intel Xeon 636 is the pick for single-threaded rendering and integer-heavy workloads, while the Intel Core Ultra 7 255HX is better for floating-point math, encryption, and overall multithreaded throughput. The Xeon 636's 146.4% lead in Cinebench R23 single-core and 64.2% lead in R15 single-core make it the obvious choice for applications that rely heavily on single-thread performance, such as legacy code or lightly threaded rendering tasks. Its 15.8% win in R23 multi-core also suggests superior sustained rendering performance over longer runs.

The Ultra 7 255HX, on the other hand, wins the overall average benchmark score (62,738 vs. 61,360) and places in the 93rd percentile of all CPUs, one point higher than the Xeon's 92nd percentile. Its 32.9% lead in floating-point math and 31.2% lead in data encryption indicate strengths in scientific computing and security workloads. The Ultra 7 also leads in PassMark single-thread by 13.7%, contradicting the Cinebench single-core results, which highlights how benchmark-specific performance can be. For a mobile platform, the Ultra 7's 55W TDP is a practical advantage, though the Xeon 636's 170W TDP reflects its workstation orientation.

Users prioritizing Cinebench R23 single-core performance should choose the Xeon 636 without hesitation. Those needing a balanced mobile processor with strong floating-point and encryption capabilities should opt for the Ultra 7 255HX. The Xeon 636's 7 benchmark wins are more impactful in their respective categories, but the Ultra 7's 10 wins, including the composite multithread and single-thread scores, give it a broader overall profile.

Architecture Differences

The two processors are built on fundamentally different architectures and manufacturing processes. The Xeon 636 uses Granite Rapids architecture on a 5 nm process fabricated by Intel, with a die size of 598 mm². The Core Ultra 7 255HX uses Arrow Lake architecture on a 3 nm process fabricated by TSMC, with a die size of 243 mm² and 17,800 million transistors. The smaller process node gives the Ultra 7 a density advantage, while the Xeon's larger die accommodates a different cache hierarchy.

The core configurations differ significantly. The Xeon 636 has 12 cores and 24 threads, relying on Hyper-Threading to double thread count. The Ultra 7 255HX has 20 cores and 20 threads, with no Hyper-Threading, meaning each core handles one thread. This explains why the Ultra 7 wins in most multi-threaded tests despite having fewer threads total; its higher core count (20 vs. 12) provides more parallel execution units.

Cache layouts also diverge. The Xeon 636 offers 112 KB of L1 cache per core, 2 MB of L2 cache per core, and 48 MB of shared L3 cache. The Ultra 7 255HX has 192 KB of L1 per core, 3 MB of L2 per core, and 30 MB of shared L3 cache. The Xeon's larger L3 cache (48 MB vs. 30 MB) likely contributes to its wins in integer math and data compression, where larger working sets can stay resident. The Ultra 7's larger per-core L1 and L2 caches may help its single-thread PassMark score.

Memory support is another key differentiator. The Xeon 636 supports quad-channel DDR5 with a memory bandwidth of 204.8 GB/s and ECC memory, making it suitable for error-sensitive workstation tasks. The Ultra 7 255HX supports dual-channel DDR5 with 102.4 GB/s bandwidth and no ECC support. The Xeon's doubled memory bandwidth is a significant advantage for memory-bound workloads, though the benchmark data does not directly isolate this effect.

The Xeon 636 also offers 80 PCIe Gen 5 lanes (CPU only) versus the Ultra 7's 20 lanes, reflecting its server/workstation market segment. The Ultra 7 includes integrated Arc Xe-LPG Graphics 64EU, while the Xeon has no integrated graphics. The Xeon uses Socket 4710, while the Ultra 7 uses BGA 2114, making the Xeon a socketed, replaceable part and the Ultra 7 a soldered mobile component.

FAQ

Q: Which processor has a higher average benchmark score?

A: The Intel Core Ultra 7 255HX has a higher average benchmark score of 62,738, compared to the Intel Xeon 636's 61,360. The Ultra 7 also ranks in the 93rd percentile of all CPUs, versus the Xeon's 92nd percentile.

Q: Why does the Xeon 636 win Cinebench R23 single-core by such a large margin?

A: The Xeon 636 scores 5,330 in Cinebench R23 single-core, while the Core Ultra 7 255HX scores 2,163, a 146.4% difference. This is the largest delta in any head-to-head benchmark, indicating a fundamental advantage in this specific workload for the Xeon's Granite Rapids architecture.

Q: Does the Core Ultra 7 255HX have more cores than the Xeon 636?

A: Yes, the Ultra 7 255HX has 20 cores and 20 threads, while the Xeon 636 has 12 cores and 24 threads. The Ultra 7 uses more physical cores without Hyper-Threading, while the Xeon relies on Hyper-Threading to reach 24 threads.

Q: What is the memory bandwidth difference between the two?

A: The Xeon 636 supports quad-channel DDR5 memory with 204.8 GB/s bandwidth, while the Core Ultra 7 255HX supports dual-channel DDR5 with 102.4 GB/s bandwidth. The Xeon also supports ECC memory, while the Ultra 7 does not.

Q: Which processor wins the PassMark multithread test?

A: The Core Ultra 7 255HX wins PassMark multithread with a score of 48,234, compared to the Xeon 636's 44,421, a 7.9% lead. This is one of the Ultra 7's 10 benchmark wins.

Q: Does either processor have integrated graphics?

A: The Core Ultra 7 255HX includes Arc Xe-LPG Graphics 64EU, while the Intel Xeon 636 has no integrated graphics (N/A). This makes the Ultra 7 suitable for systems without a discrete GPU.

Where Each One Wins

The Intel Xeon 636 wins in scenarios requiring extreme single-thread performance in Cinebench, as evidenced by its 146.4% lead in R23 single-core and 64.2% lead in R15 single-core. It also wins in integer math (8.8% lead), data compression (6.8% lead), extended instructions (4.9% lead), and physics (24.6% lead). These results point to workloads like integer-heavy database operations, compression algorithms, and physics simulations running on workstations with ECC memory and quad-channel bandwidth.

The Intel Core Ultra 7 255HX wins in floating-point math (32.9% lead), data encryption (31.2% lead), find prime numbers (36.2% lead), and random string sorting (13.1% lead), plus the composite PassMark single-thread and multithread tests. Its strengths in floating-point and encryption make it suitable for scientific computing, cryptographic tasks, and general mobile productivity. The Ultra 7's 20 physical cores also give it an edge in Cinebench R15 and R20 multi-core tests, though it loses in R23 multi-core.

For a mobile workstation or high-end laptop, the Ultra 7 255HX's 55W TDP and integrated graphics make it a practical choice where power efficiency and GPU output matter. For a rack-mounted server or desktop workstation with dedicated cooling, the Xeon 636's 170W TDP, 80 PCIe Gen 5 lanes, and quad-channel memory bandwidth offer superior expandability and memory throughput. The Xeon's launch MSRP is $639, while the Ultra 7 has no listed launch MSRP. Ultimately, the Xeon 636 is the specialist for single-threaded rendering and integer workloads, while the Ultra 7 255HX is the generalist for floating-point, encryption, and mobile multitasking.