Intel Core Ultra 7 265K vs Intel Core Ultra X9 378H Comparison

Head-to-Head Benchmarks

The recorded data shows a decisive overall victory for the Intel Core Ultra 7 265K, with 16 benchmark wins out of 17 head-to-head comparisons. The single exception is a dramatic reverse in Cinebench R23 single-core testing, where the Intel Core Ultra X9 378H scores 4595 against 2020, a 56% advantage. This outlier is striking because in every other single-threaded test the 265K leads, suggesting the X9 378H has a specialized performance profile rather than a general single-core superiority.

The most substantial margins appear in PassMark workloads. Data compression shows the 265K at 665554 versus 386591, a 72.2% gap. Extended instructions follow at 73.5% (54333 vs 31315), floating point math at 65.6% (189629 vs 114500), and random string sorting at 78.6% (79752 vs 44648). Data encryption delivers a 61.7% lead (48246 vs 29840), while integer math sits at 54.7% (143242 vs 92603). These results indicate the desktop part handles arithmetic-heavy and data-manipulation tasks with substantially higher throughput.

The Cinebench multi-core results are more nuanced. In R15 and R20, the 265K leads by exactly 53% (5020 vs 3281 and 20918 vs 13672 respectively). However, in R23 multi-core the margin shrinks to just 10.1% (35850 vs 32553). This compression suggests that as the workload scales in duration or memory pressure, the X9 378H narrows the gap considerably, a pattern consistent with a mobile processor that can sustain competitive multi-threaded output despite lower absolute clock speeds.

PassMark multi-thread shows the 265K at 58594 versus 38298, a 53% advantage, while physics testing yields only a 9.6% delta (3731 vs 3404). Single-thread PassMark scores are close by comparison: 4928 versus 4453, a 10.7% edge for the 265K. This pattern reinforces that the X9 378H is not uniformly slower; its weaknesses are concentrated in memory-bandwidth-sensitive and integer-heavy operations, while its strengths emerge in bursty single-core scenarios.

Architecture Differences

The two processors occupy different market positions within Intel's lineup. The Intel Core Ultra 7 265K belongs to Core Ultra Series 2, uses the Arrow Lake architecture (codename Arrow Lake-S), and targets the desktop segment. The Intel Core Ultra X9 378H belongs to Core Ultra Series 3, uses the Panther Lake architecture (codename Panther Lake-H), and targets mobile devices. Both are built on a 3 nm process node, but the foundry differs: TSMC fabricates the 265K, while Intel fabricates the 378H. The 265K has a transistor count of 17,800 million and a die size of 243 mm²; the 378H has no recorded transistor or die size data.

Core and thread configurations differ significantly. The 265K provides 20 cores and 20 threads, while the 378H offers 16 cores and 16 threads. Neither uses simultaneous multithreading, so thread counts equal core counts. Base and boost clocks diverge substantially: the 265K runs at 3.90 GHz base and 5.50 GHz boost, versus 2.00 GHz base and 5.00 GHz boost for the 378H. The desktop part therefore has a 1.90 GHz base clock advantage and a 0.50 GHz boost advantage.

Cache hierarchies share the same L1 capacity at 192 KB per core, but L2 and L3 differ. The 265K has 3 MB L2 per core and 30 MB shared L3. The 378H has 2.5 MB L2 per core and 18 MB shared L3. This means the desktop processor doubles the total L3 capacity and provides larger per-core L2, directly contributing to its dominance in cache-sensitive workloads such as data compression and random string sorting.

Memory support also separates the two. The 265K uses DDR5 with dual-channel configuration and 102.4 GB/s bandwidth, plus ECC memory support. The 378H uses LPDDR5X with dual-channel configuration and 153.6 GB/s bandwidth, without ECC. Despite the mobile part having 50% more memory bandwidth, the desktop part's larger cache and higher clocks evidently compensate in most benchmarks. PCIe capability differs as well: the 265K exposes Gen 5 with 20 CPU lanes, while the 378H exposes Gen 5 with only 4 CPU lanes.

Integrated graphics are distinct. The 265K carries Arc Xe-LPG Graphics with 64 execution units. The 378H carries Arc B390. The 265K has an unlocked multiplier, the 378H does not. The 265K uses Intel Socket 1851, the 378H uses Intel BGA 2540. The 265K was released on 2024-10-23 with a launch MSRP of $394; the 378H has a release date of 2026-04-03 and no recorded launch MSRP. The 265K has a part number of SRQCW, while the 378H has an unknown part number.

FAQ

Q: Which processor has the higher boost clock?

A: The Intel Core Ultra 7 265K reaches 5.50 GHz boost, while the Intel Core Ultra X9 378H tops out at 5.00 GHz.

Q: Why does the X9 378H win Cinebench R23 single-core despite having a lower boost clock?

A: The recorded data shows a 56% delta in favor of the 378H (4595 vs 2020). This result suggests the Panther Lake architecture can deliver higher single-thread performance in certain workloads, but the same processor loses in PassMark single-thread testing by 10.7%, indicating the R23 result is workload-specific rather than a general single-core advantage.

Q: How do the cache sizes compare?

A: Both have 192 KB L1 per core. The 265K has 3 MB L2 per core and 30 MB shared L3. The 378H has 2.5 MB L2 per core and 18 MB shared L3.

Q: Do these processors support ECC memory?

A: Yes, the 265K supports ECC memory. The 378H does not.

Q: Which processor has more PCIe lanes?

A: The 265K provides 20 Gen 5 CPU lanes. The 378H provides 4 Gen 5 CPU lanes.

Q: What is the average benchmark score for each?

A: The 265K has an average benchmark score of 70879, placing it in the 94th percentile. The 378H has an average benchmark score of 47468, placing it in the 89th percentile.

Specification Differences

| Specification | Intel Core Ultra 7 265K | Intel Core Ultra X9 378H |

|---|---|---|

| Series | Core Ultra Series 2 | Core Ultra Series 3 |

| Architecture | Arrow Lake | Panther Lake |

| Codename | Arrow Lake-S | Panther Lake-H |

| Generation | Ultra 7 (Arrow Lake) | Ultra X9 (Panther Lake-H) |

| Foundry | TSMC | Intel |

| Transistors | 17,800 million | Not recorded |

| Die Size | 243 mm² | Not recorded |

| Cores | 20 | 16 |

| Threads | 20 | 16 |

| Base Clock | 3.90 GHz | 2.00 GHz |

| Boost Clock | 5.50 GHz | 5.00 GHz |

| TDP | 125 | 25 |

| Socket | Intel Socket 1851 | Intel BGA 2540 |

| L2 Cache | 3 MB (per core) | 2.5 MB (per core) |

| L3 Cache | 30 MB (shared) | 18 MB (shared) |

| Memory Support | DDR5 | LPDDR5X |

| Memory Bandwidth | 102.4 GB/s | 153.6 GB/s |

| ECC Memory | Yes | No |

| PCIe | Gen 5, 20 Lanes (CPU only) | Gen 5, 4 Lanes (CPU only) |

| Integrated Graphics | Arc Xe-LPG Graphics 64EU | Arc B390 |

| Market Segment | Desktop | Mobile |

| Release Date | 2024-10-23 | 2026-04-03 |

| Multiplier Unlocked | Yes | No |

| Part Number | SRQCW | Unknown |

| Launch MSRP | $394 | Not recorded |

Where Each One Wins

The Intel Core Ultra 7 265K wins in almost every measured scenario. Its 53% advantages in Cinebench R15 and R20 multi-core, along with a 53% lead in PassMark multi-thread, establish it as the stronger choice for parallel rendering, video encoding, and heavily threaded productivity. The 72.2% data compression win and 78.6% random string sorting win make it the superior option for database workloads, file archiving, and any task that manipulates large in-memory datasets. The 65.6% floating point math advantage favors scientific computing and simulation tasks. The 61.7% encryption lead supports secure communication and storage workloads. Integer math at 54.7% ahead favors general application logic and compilation tasks. The 37.5% find prime numbers lead reinforces its arithmetic throughput. The 73.5% extended instructions win indicates better support for SIMD and specialized instruction sets.

The Intel Core Ultra X9 378H wins only in Cinebench R23 single-core, where its 4595 score beats the 265K's 2020 by 56%. This single result suggests that in certain single-threaded rendering scenarios, the mobile part can outperform the desktop part. However, the 378H loses PassMark single-thread by 10.7%, so this is not a blanket single-core victory. The 378H also shows competitive multi-core R23 performance, trailing by only 10.1%, and physics testing by just 9.6%. These narrower margins indicate that in sustained multi-threaded workloads with moderate cache pressure, the mobile processor can approach the desktop part's performance. The 378H also offers higher memory bandwidth at 153.6 GB/s versus 102.4 GB/s, which could benefit memory-bandwidth-bound tasks even though the recorded benchmarks do not show a win in such tests. Its 25 TDP versus 125, combined with mobile packaging, positions it for thermally constrained systems where the desktop part cannot be installed.