Intel Core i5-8265U vs Intel Core i5-8365U Comparison

The Intel Core i5-8365U and Intel Core i5-8265U are two closely related Whiskey Lake-U mobile processors, but the benchmark data shows a clear, consistent performance hierarchy between them. Both are 4-core, 8-thread parts aimed at thin-and-light laptops, yet the i5-8365U holds a decisive edge across every single benchmark recorded, making it the stronger option for users who prioritize compute performance over other considerations.

Head-to-Head Benchmarks

The most striking pattern in the data is the complete sweep: the Intel Core i5-8365U wins all 17 head-to-head comparisons against the Intel Core i5-8265U. The largest margins appear in the Cinebench suite, where the i5-8365U’s higher boost clock translates into substantial gains. In Cinebench R15 multi-core, the i5-8365U scores 509 versus 451 for the i5-8265U, a 12.9% advantage. The single-core R15 test tells a similar story, with a score of 71 against 63, a 12.7% lead. This pattern holds across newer Cinebench versions: R20 multi-core shows 2121 vs 1882 (12.7% delta), and R23 multi-core shows 5050 vs 4482 (12.7% delta). The consistency of these margins—hovering near 12.7% to 12.9%—suggests a fixed architectural advantage rather than a workload-specific anomaly.

Single-threaded performance follows the same trajectory. Cinebench R20 single-core scores 299 for the i5-8365U versus 265 for the i5-8265U, a 12.8% difference. Cinebench R23 single-core is nearly identical in relative terms, with 713 vs 632, a 12.8% delta. These results align with the boost clock difference between the two parts: the i5-8365U boosts to 4.10 GHz, while the i5-8265U tops out at 3.90 GHz. The data suggests that the extra 200 MHz of boost headroom is the primary driver of these consistent double-digit gains in both lightly and heavily threaded rendering workloads.

Outside of Cinebench, the margins shrink considerably, but the i5-8365U still wins every test. In PassMark’s integer math benchmark, the i5-8365U scores 22021 against 21560, a 2.1% lead. Floating-point math shows a similar gap: 13110 vs 12963, a 1.1% advantage. Data compression is nearly a tie, with 76239 vs 76049, a mere 0.2% difference, indicating that this workload is less sensitive to clock speed and more constrained by memory or cache behavior. Data encryption shows a 2.3% edge (2006 vs 1961), and extended instructions (SIMD-heavy work) favor the i5-8365U by 3.5% (5074 vs 4904). The PassMark multi-thread score gives the i5-8365U a 2.4% win (5976 vs 5838), while single-thread scores are 2073 vs 2030, a 2.1% gap. Even niche tests like prime number finding (19 vs 18, 5.6% delta) and physics simulation (422 vs 405, 4.2% delta) show the i5-8365U pulling ahead.

The overall average benchmark score reinforces this picture: the i5-8365U averages 8708, while the i5-8265U averages 8568. That places the i5-8365U in the 65th percentile of all CPUs, versus the 64th percentile for the i5-8265U. The nearest rival data also contextualizes these scores. The i5-8365U’s average score is within 0.4% of the Intel Core i9-13900E and 0.5% of the Intel Core i7-8565U, both of which post slightly lower averages (8676 and 8665, respectively). The i5-8265U, meanwhile, sits essentially level with the Intel Core i5-8250U (8577, -0.1% delta) and the Intel Core i7-10510U (8580, -0.1% delta). In practical terms, the i5-8365U is a meaningful step up in compute performance, even if both chips occupy the same performance tier relative to the broader market.

Architecture Differences

At the architectural level, the two processors are nearly identical, which makes the performance gap all the more interesting. Both use the Whiskey Lake architecture (codename Whiskey Lake-U) and are built on Intel’s 14 nm process node. They share the same core configuration: 4 cores and 8 threads, with a base clock of 1600 MHz for both. The cache hierarchy is identical as well, with 64 KB of L1 cache per core, 256 KB of L2 per core, and a shared 6 MB L3 cache.

The defining difference is the boost clock. The i5-8365U boosts to 4.10 GHz, while the i5-8265U boosts to 3.90 GHz. That 200 MHz gap is the only clock-speed difference between the two, and it explains the consistent double-digit margins in Cinebench. Both chips carry a 15 W TDP, which means the i5-8365U is achieving its higher performance within the same thermal envelope—a notable efficiency point for laptop designs.

Other specifications are identical. Both support DDR4 memory in a dual-channel configuration with a memory bandwidth of 38.4 GB/s. Neither supports ECC memory. Both use the Intel BGA 1528 socket and offer PCIe Gen 3 with 16 lanes (CPU only). Integrated graphics are the same UHD Graphics 620 on both parts. The process node, foundry (Intel), and lack of an unlocked multiplier are also shared. The release dates differ, with the i5-8265U launching on 2018-09-30 and the i5-8365U following on 2019-04-15, but both are now end-of-life products. The part numbers differ (SRF9Z for the i5-8365U, SRFFXSREJQSREJR for the i5-8265U), but that is a manufacturing identifier, not a functional difference.

The Verdict

The data is unambiguous: the Intel Core i5-8365U is the faster processor in every measured workload. If a laptop comes with the i5-8365U, it will deliver roughly 12.7% better multi-core rendering performance in Cinebench R23 and a similar 12.8% advantage in single-core rendering, compared to the i5-8265U. For users who run CPU-intensive tasks like video encoding, 3D rendering, or heavy spreadsheet calculations, that translates into noticeably shorter wait times. The PassMark suite shows smaller but consistent gains—ranging from 0.2% in data compression to 5.6% in prime number finding—so even mixed workloads will see a slight improvement.

The i5-8265U is not a bad chip; its average benchmark score of 8568 puts it in the 64th percentile, and it trades blows with the Intel Core i7-10510U and the Intel Core i5-8250U. But it is strictly slower than the i5-8365U in this comparison, with zero wins across all 17 head-to-head tests. The only reason to choose the i5-8265U would be availability or price in a specific laptop model, but from a pure performance standpoint, the i5-8365U is the clear pick. For anyone deciding between two otherwise-equivalent laptops, the benchmark data says to take the i5-8365U. The extra boost clock delivers real, measurable performance without any increase in TDP, making it the superior mobile processor for compute-heavy workloads.

Specification Differences

The two processors differ in only a few specification fields. The most important is the boost clock: the Intel Core i5-8365U has a maximum boost of 4.10 GHz, while the Intel Core i5-8265U has a maximum boost of 3.90 GHz. This is the sole clock-speed difference, as both have a base clock of 1600 MHz. The release dates also differ, with the i5-8265U launching on 2018-09-30 and the i5-8365U launching on 2019-04-15. The part numbers are different as well: SRF9Z for the i5-8365U and SRFFXSREJQSREJR for the i5-8265U. Notably, the launch MSRP is identical for both at $297. All other specification fields—cores (4), threads (8), TDP (15 W), socket (Intel BGA 1528), architecture (Whiskey Lake), process node (14 nm), cache (64 KB L1 per core, 256 KB L2 per core, 6 MB L3 shared), memory support (DDR4 dual-channel, 38.4 GB/s), ECC support (false), PCIe (Gen 3, 16 lanes), integrated graphics (UHD Graphics 620), and multiplier unlock status (false)—are exactly the same.

FAQ

Q: Which processor is faster in multi-core workloads?

A: The Intel Core i5-8365U wins every multi-core benchmark. In Cinebench R23 multi-core, it scores 5050 versus 4482 for the i5-8265U, a 12.7% advantage. The PassMark multi-thread test shows a smaller 2.4% edge (5976 vs 5838).

Q: How big is the single-threaded performance gap?

A: The i5-8365U leads by 12.8% in Cinebench R23 single-core (713 vs 632) and by 2.1% in PassMark single-thread (2073 vs 2030). The larger Cinebench margin reflects the higher boost clock of 4.10 GHz versus 3.90 GHz.

Q: Do the two processors have the same core and thread configuration?

A: Yes. Both have 4 cores and 8 threads, with a base clock of 1600 MHz. They also share the same 14 nm process node and Whiskey Lake architecture.

Q: Is there any workload where the i5-8265U wins?

A: No. The head-to-head data shows 17 wins for the i5-8365U and 0 wins for the i5-8265U. The closest result is PassMark data compression, where the i5-8365U leads by only 0.2% (76239 vs 76049).

Q: Are the cache sizes different between the two?

A: No. Both have 64 KB of L1 cache per core, 256 KB of L2 per core, and a shared 6 MB L3 cache. The identical cache hierarchy means the performance difference comes from the boost clock, not memory architecture.

Q: What is the average benchmark score difference?

A: The i5-8365U has an average benchmark score of 8708, while the i5-8265U averages 8568. This places them in the 65th and 64th percentiles of all CPUs, respectively.