Intel Core i5-8365U vs Intel Core i7-8550U Comparison

Where Each One Wins

The benchmark data splits these two mobile processors into a clear pattern. The Intel Core i5-8365U wins 15 of the 17 recorded head-to-head tests, while the Intel Core i7-8550U takes only 2. That dominance is not uniform, however. The i5-8365U holds its advantage across nearly every category, but the i7-8550U shows strength in two specific workloads that reveal different design priorities.

The i5-8365U leads in all six Cinebench tests. In multi-core rendering, it scores 509 in Cinebench R15 versus 496 for the i7-8550U, a 2.6% gap. The R20 multi-core result is 2121 against 2068, also 2.6%. The R23 multi-core test shows 5050 versus 4926, a 2.5% edge. Single-core results follow the same pattern: 71 versus 69 in R15 single-core (2.9%), 299 versus 291 in R20 single-core (2.7%), and 713 versus 695 in R23 single-core (2.6%). These are consistent, modest margins that point to a slightly higher sustained clock behavior in the i5-8365U, despite its lower base clock of 1600 MHz compared to 1800 MHz on the i7-8550U. The boost clock tells part of the story: the i5-8365U boosts to 4100 MHz, while the i7-8550U reaches 4000 MHz.

The Passmark suite reinforces that lead. Integer math shows 22021 for the i5-8365U versus 20770 for the i7-8550U, a 6.0% advantage. Floating-point math lands at 13110 versus 12523, a 4.7% gap. Extended instructions, which cover SIMD and cryptography-style workloads, show the largest single delta: 5074 versus 4665, an 8.8% advantage for the i5-8365U. Data compression scores 76239 versus 74223 (2.7%), data encryption 2006 versus 1944 (3.2%), and random string sorting 10256 versus 9902 (3.6%). The multi-thread Passmark score is 5976 versus 5835 (2.4%), and the single-thread score is 2073 versus 2021 (2.6%).

The two wins for the i7-8550U are worth examining closely. In Passmark find prime numbers, the i7-8550U scores 22 versus 19 for the i5-8365U, a 13.6% advantage. This is the largest delta in either direction across the entire benchmark set. Prime-number finding is a heavily integer-dependent, branch-heavy workload that can respond well to cache hierarchy. The i7-8550U has 8 MB of shared L3 cache, while the i5-8365U has only 6 MB. That extra 2 MB may explain the gap. The second win comes in Passmark physics, where the i7-8550U scores 451 versus 422, a 6.4% edge. Physics simulations often rely on rigid-body calculations and can be sensitive to memory latency and cache capacity as well.

Looking at the broader database context, the i5-8365U sits at the 65th percentile among all CPUs, with an average benchmark score of 8708. The i7-8550U sits at the 64th percentile with an average of 8407. That 301-point gap in average score is roughly 3.6%, which aligns with the typical head-to-head deltas. Both processors are close enough that the database places them in similar competitive tiers, but the i5-8365U consistently edges ahead.

The nearest rivals for the i5-8365U include the Intel Core i9-13900E with an average score of 8676 (0.4% behind), the Intel Core i7-8565U at 8665 (0.5% behind), the AMD EPYC 7601 at 8619 (1.0% behind), and the Intel Core i7-10510U at 8580 (1.5% behind). For the i7-8550U, the nearest rivals are the Intel Xeon Gold 5318N at 8433 (0.3% ahead), the Intel Core i5-10210U at 8344 (0.7% behind), the Intel Xeon Gold 5320T at 8316 (1.1% behind), and the Intel Xeon Platinum 8268 at 8315 (1.1% behind). This means the i5-8365U competes with newer and higher-tier parts, while the i7-8550U sits closer to server-class Xeons in average score, though those Xeons are far different in core counts and power envelopes.

The Verdict

For most workloads, the Intel Core i5-8365U is the stronger processor. Every Cinebench generation tested, from R15 through R23, shows the i5-8365U ahead in both single-core and multi-core rendering. The Passmark suite confirms this across integer math, floating-point math, extended instructions, data compression, data encryption, random string sorting, and both single-thread and multi-thread aggregate scores. If the task is general productivity, code compilation, spreadsheet work, or any mixed integer and floating-point load, the data says pick the i5-8365U.

The i7-8550U has a narrow but real niche. In prime-number finding, it beats the i5-8365U by 13.6%, the largest margin in any test. In physics simulations, it leads by 6.4%. Both workloads benefit from the i7-8550U's larger 8 MB L3 cache. Users who run mathematical sieving, certain computational number theory, or physics engines that stress cache residency may see better results on the i7-8550U. That said, these are specialized cases. The i5-8365U wins the overall average benchmark score, the higher percentile ranking, and the overwhelming majority of individual tests.

The production status differs as well. The i5-8365U is marked as end-of-life, while the i7-8550U is listed as active. That may influence availability in current systems, but the benchmark data does not factor into supply decisions. The i5-8365U also has a recorded launch MSRP of $297, while no launch MSRP is listed for the i7-8550U.

For a buyer choosing between two used or refurbished laptops, the i5-8365U offers better all-around performance in the recorded measurements. For a specific scientific or simulation workload that matches the i7-8550U's two winning tests, the extra cache may tip the balance. The verdict from the database is clear: 15 wins versus 2 wins favors the i5-8365U, and the average benchmark score confirms it.

Head-to-Head Benchmarks

The most decisive single result is Passmark extended instructions. The i5-8365U scores 5074, while the i7-8550U scores 4665. That 8.8% gap is the largest margin of victory for the i5-8365U in any test. Extended instructions typically cover AVX and SSE workloads, so the i5-8365U's Whiskey Lake architecture appears to execute these more efficiently than the i7-8550U's Kaby Lake design.

The second-largest win for the i5-8365U is Passmark integer math, where it scores 22021 against 20770, a 6.0% edge. This is a high-volume test that stresses core execution and pipeline throughput. The i5-8365U also takes floating-point math by 4.7% (13110 versus 12523), which is notable because floating-point performance often correlates with compiler optimization and microarchitectural improvements.

The Cinebench results are tightly clustered. All six tests show a delta between 2.5% and 2.9%, with no test exceeding 3%. This consistency suggests the i5-8365U maintains a small but reliable clock advantage under sustained load. The boost clock difference, 4100 MHz versus 4000 MHz, is 2.5%, which matches the Cinebench deltas almost exactly. The base clock is actually lower on the i5-8365U (1600 MHz versus 1800 MHz), but the higher boost clock and the Whiskey Lake architecture compensate.

In memory-related tasks, the i5-8365U leads data compression by 2.7% (76239 versus 74223) and random string sorting by 3.6% (10256 versus 9902). Data encryption shows a 3.2% gap (2006 versus 1944). None of these are large enough to call one processor transformative over the other, but they all point in the same direction.

The i7-8550U's two wins are not flukes. In find prime numbers, the 19 versus 22 result gives the i7-8550U a 13.6% advantage, which is the single largest delta in either direction. In physics, the 422 versus 451 result is a 6.4% edge. Both tests are known to be sensitive to cache size. The i7-8550U's 8 MB L3 cache versus the i5-8365U's 6 MB L3 cache is the most plausible explanation. The prime-number workload involves repeated modulo operations on a working set that may fit in the larger cache, and physics engines often keep collision matrices resident.

The multi-thread Passmark score shows a 2.4% gap (5976 versus 5835), which is slightly smaller than the Cinebench multi-core deltas. The single-thread Passmark score is 2073 versus 2021, a 2.6% gap, matching the Cinebench single-core pattern. Both processors have 4 cores and 8 threads, so the thread-count parity means the differences come from clock speed and microarchitecture, not core count.

FAQ

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

A: The Intel Core i5-8365U. In Cinebench R23 multi-core, it scores 5050 versus 4926 for the i7-8550U, a 2.5% advantage. The R20 multi-core test shows 2121 versus 2068 (2.6%), and R15 multi-core shows 509 versus 496 (2.6%).

Q: Why does the i7-8550U win the prime-number test by such a large margin?

A: The i7-8550U has 8 MB of shared L3 cache, while the i5-8365U has 6 MB. The prime-number workload (score 22 versus 19, a 13.6% advantage) is likely cache-sensitive, and the larger cache lets the i7-8550U keep more working data resident.

Q: Do both processors have the same core and thread counts?

A: Yes. Both the i5-8365U and the i7-8550U have 4 cores and 8 threads. The performance differences in the recorded benchmarks therefore come from clock speeds, cache size, and microarchitecture, not from core count.

Q: What is the biggest percentage difference in any head-to-head test?

A: The largest is in Passmark find prime numbers, where the i7-8550U leads by 13.6%. The largest i5-8365U win is in Passmark extended instructions, with an 8.8% margin (5074 versus 4665).

Q: How do the two processors compare in average benchmark score?

A: The i5-8365U has an average benchmark score of 8708, placing it at the 65th percentile. The i7-8550U has an average of 8407, at the 64th percentile. That is a difference of roughly 3.6% in average score.

Q: Are there any architectural differences beyond cache size?

A: Yes. The i5-8365U uses the Whiskey Lake architecture on socket Intel BGA 1528, while the i7-8550U uses Kaby Lake on socket Intel BGA 1356. The i5-8365U boosts to 4100 MHz, and the i7-8550U boosts to 4000 MHz. The process node is the same at 14 nm for both.

Architecture Differences

The two processors share a 14 nm process node and both come from Intel, but they represent different microarchitectures. The i5-8365U is built on Whiskey Lake, with the codename Whiskey Lake-U, and belongs to the Core i5 generation from that family. The i7-8550U is built on Kaby Lake, with the codename Kaby Lake-R, and belongs to the Core i7 Kaby Lake-U Refresh generation. Whiskey Lake is a refinement of Kaby Lake, so the differences are incremental rather than fundamental, but the benchmark data shows measurable effects.

The socket differs. The i5-8365U uses Intel BGA 1528, while the i7-8550U uses Intel BGA 1356. This means the two processors are not physically interchangeable in the same motherboard. Any system designed for one will not accept the other without a board change. That is a practical consideration for upgrades, though the benchmark data does not comment on it.

The cache hierarchy is where the clearest architectural split appears. Both processors have 64 KB of L1 cache per core and 256 KB of L2 cache per core. The shared L3 cache differs: the i5-8365U has 6 MB, and the i7-8550U has 8 MB. That 2 MB difference is the most likely cause of the i7-8550U's wins in prime-number finding and physics, as those workloads can exceed the smaller cache capacity.

Clock speeds also differ. The i5-8365U has a base clock of 1600 MHz and a boost clock of 4100 MHz. The i7-8550U has a base clock of 1800 MHz and a boost clock of 4000 MHz. The i5-8365U starts lower but boosts higher, which explains why it wins single-core tests by roughly 2.6% to 2.9% despite the i7-8550U's higher base frequency. The sustained boost behavior, likely aided by Whiskey Lake's improved power management, gives the i5-8365U an edge under load.

Both processors have 4 cores and 8 threads, and both are locked (multiplier unlocked is false for each). Both have integrated graphics: UHD Graphics 620 on the i5-8365U and UHD 620 on the i7-8550U. Both support DDR4 memory with dual-channel access on the i5-8365U, which lists a memory bandwidth of 38.4 GB/s. The i7-8550U does not have a recorded memory bus or bandwidth in the database, so a direct comparison is not possible. Neither supports ECC memory.

The PCIe configuration is recorded only for the i5-8365U: Gen 3 with 16 lanes (CPU only). The i7-8550U has no recorded PCIe data. The i5-8365U also has a die size recorded only for the i7-8550U, which is 123 mm². The i5-8365U does not have a die size or transistor count listed.

The release dates differ by about 20 months. The i7-8550U was released in August 2017, and the i5-8365U was released in April 2019. The i7-8550U remains in active production, while the i5-8365U is marked as end-of-life. The part numbers are SR3LC for the i7-8550U and SRF9Z for the i5-8365U.

The market segment for both is mobile, and both have a 15 W TDP. The i5-8365U has a launch MSRP of $297, while the i7-8550U has no launch MSRP recorded. Neither processor has an unlocked multiplier, so overclocking is not part of the story.

In the database context, the i5-8365U's nearest rivals include the i9-13900E, i7-8565U, EPYC 7601, and i7-10510U. The i7-8550U's nearest rivals include the Xeon Gold 5318N, i5-10210U, Xeon Gold 5320T, and Xeon Platinum 8268. This placement shows that the i5-8365U, despite being a lower-tier name (i5 versus i7), outperforms its direct competitor in the same family and lands near much higher-tier desktop and server parts in average score. The architectural refinements in Whiskey Lake, combined with a higher boost clock, are enough to overcome the i7-8550U's larger cache in the majority of measured workloads.