Intel Core i5-8350U vs Intel Core i7-8650U Comparison

The Intel Core i5-8350U and Intel Core i7-8650U are two 15-watt Kaby Lake-R mobile processors designed for ultrabooks and thin-and-light laptops. Both share the same core count, socket, integrated graphics, and manufacturing process, yet the data shows the i7-8650U holds a consistent, if modest, edge in most compute workloads. The i5-8350U counterattacks in a handful of specialized tasks, making the choice between them a matter of workload priorities rather than a clear-cut generational leap. Benchmark results indicate the two chips sit within 0.7% of each other in average benchmark score, with the i5-8350U posting 8998 and the i7-8650U posting 8932, placing both in the 65th percentile of all CPUs.

The Verdict

For users whose work is dominated by mainstream productivity, rendering, and single-threaded responsiveness, the Intel Core i7-8650U is the safer pick. It wins 11 of the 17 head-to-head benchmarks, including every Cinebench test and the all-important PassMark single-thread score. The i7-8650U delivers 2103 in PassMark single-thread versus 1996 for the i5-8350U, a 5.1% advantage that translates to snappier application launches and faster code compilation. In multi-core Cinebench R23, the i7 posts 5253 against 5173 for the i5, a 1.5% lead that persists across R15, R20, and R23 runs. The i7 also dominates the physics simulation test, scoring 472 versus 428, a 9.3% gap that favors simulation and scientific workloads.

The Intel Core i5-8350U is not without its niche. It wins 6 of the 17 benchmarks, and those wins cluster around data processing and math-heavy integer tasks. Data compression favors the i5 at 79781 versus 78936, a 1.1% edge, and integer math shows a similar 1.1% lead at 22244 versus 22007. Extended instruction throughput is the i5’s biggest win: 5243 versus 5042, a 4% margin. If your workload involves heavy data compression, encryption, or extended instruction sets, the i5-8350U offers a measurable, if small, performance benefit. For everyone else, the i7-8650U’s higher boost clock and larger L3 cache make it the more versatile processor. The data clearly favors the i7 for general use, while the i5 is a specialist tool for specific throughput-bound tasks.

Architecture Differences

Both processors are built on Intel’s Kaby Lake architecture, specifically the Kaby Lake-R refresh, and are fabricated on Intel’s 14 nm process. The die size is identical at 123 mm², and both use the Intel BGA 1356 socket. The core and thread counts match at 4 cores and 8 threads, with a TDP of 15 watts. The integrated graphics are also the same: Intel UHD 620. The foundry is Intel for both parts, and neither has an unlocked multiplier.

The key architectural divergence lies in clock speeds and cache. The i7-8650U has a base clock of 1900 MHz and a boost clock of 4.20 GHz, while the i5-8350U runs lower at 1700 MHz base and 3.60 GHz boost. This 600 MHz boost clock advantage is the primary driver behind the i7’s single-thread and multi-thread wins. The L3 cache also differs: the i7-8650U has 8 MB of shared L3 cache, while the i5-8350U is limited to 6 MB. This extra 2 MB of cache helps the i7 in cache-sensitive workloads like physics and prime number finding. Both chips share the same L1 cache at 64 KB per core and L2 at 256 KB per core. Memory support is DDR4 for both, with no ECC support. The part numbers differ, with the i5-8350U being SR3L9 and the i7-8650U being SR3L8, and both were released on the same date in August 2017. The production status is active for both.

Head-to-Head Benchmarks

The most consistent pattern in the head-to-head data is the i7-8650U’s sweep of the Cinebench suite. In Cinebench R15 multi-core, the i7 scores 529 against 521 for the i5, a 1.5% difference. The single-core R15 test shows 74 versus 73, a 1.4% edge. Moving to Cinebench R20, the multi-core scores are 2206 for the i7 and 2172 for the i5, again a 1.5% gap, while single-core is 311 versus 306, a 1.6% difference. Cinebench R23 follows the identical trend: multi-core 5253 versus 5173 (1.5% lead), single-core 741 versus 730 (1.5% lead). These results indicate that the i7’s clock advantage scales uniformly across all Cinebench versions, regardless of the workload intensity.

The i7-8650U also shines in PassMark’s single-threaded and physics tests. The single-thread score of 2103 is 5.1% higher than the i5’s 1996, and the physics score of 472 is 9.3% higher than 428. The prime number finding test shows the largest percentage gap of any benchmark, with the i7 scoring 22 versus 19, a 13.6% advantage. This suggests the i7’s higher boost clock and larger cache are particularly effective in algorithmic integer loops. The multithread test also favors the i7 at 6193 versus 6129, a 1% lead.

The i5-8350U’s wins are smaller in percentage terms but consistent across several PassMark tests. The extended instructions test is its strongest: 5243 versus 5042, a 4% win. Data compression shows 79781 versus 78936, a 1.1% edge, and integer math is 22244 versus 22007, also 1.1%. Floating point math slightly favors the i5 at 13422 versus 13299, a 0.9% lead. Data encryption is nearly a tie, with the i5 at 2075 and the i7 at 2067, a 0.4% margin. Random string sorting goes to the i5 at 10651 versus 10485, a 1.6% win. These results suggest the i5-8350U has a minor architectural efficiency advantage in certain data manipulation instructions, despite its lower clock speeds.

Specification Differences

The specification table shows exactly where the two chips diverge. The base clock is 1700 MHz for the i5-8350U and 1900 MHz for the i7-8650U, a 200 MHz difference. The boost clock is the more significant gap: 3.60 GHz for the i5 versus 4.20 GHz for the i7, a 600 MHz advantage. L3 cache is 6 MB shared on the i5 and 8 MB shared on the i7, a 2 MB difference. The part numbers differ (SR3L9 vs SR3L8), and the generation labels reflect the product tier: Core i5 (Kaby Lake-U Refresh) versus Core i7 (Kaby Lake-U Refresh). All other listed specifications are identical, including cores (4), threads (8), TDP (15 watts), socket (BGA 1356), architecture (Kaby Lake), codename (Kaby Lake-R), process node (14 nm), die size (123 mm²), L1 cache (64 KB per core), L2 cache (256 KB per core), memory support (DDR4), integrated graphics (UHD 620), ECC support (false), market segment (Mobile), production status (Active), release date (August 2017), and multiplier unlock (false).

FAQ

Q: Which processor has the higher boost clock?

A: The Intel Core i7-8650U has a boost clock of 4.20 GHz, compared to 3.60 GHz for the Intel Core i5-8350U.

Q: Why does the i7-8650U win the Cinebench tests by such a consistent margin?

A: The i7’s higher base clock (1900 MHz vs 1700 MHz) and boost clock (4.20 GHz vs 3.60 GHz) provide a uniform advantage across all Cinebench R15, R20, and R23 tests, with the i7 leading by 1.4% to 1.6% in every case.

Q: In which benchmark does the i5-8350U have its largest victory?

A: The i5-8350U wins the PassMark extended instructions test by 4%, scoring 5243 against the i7’s 5042.

Q: What is the biggest percentage difference between the two chips in any benchmark?

A: The PassMark find prime numbers test shows the largest gap, with the i7-8650U scoring 22 versus 19 for the i5-8350U, a 13.6% difference.

Q: Do the two processors have the same amount of L3 cache?

A: No, the i7-8650U has 8 MB of shared L3 cache, while the i5-8350U has 6 MB of shared L3 cache.

Q: Are there any benchmarks where the two processors are nearly tied?

A: Yes, PassMark data encryption is extremely close, with the i5-8350U at 2075 and the i7-8650U at 2067, a 0.4% difference.

Where Each One Wins

The Intel Core i7-8650U is the clear winner for general-purpose computing, rendering, and any workload that benefits from higher single-thread performance. Its wins span the entire Cinebench suite, PassMark single-thread (2103 vs 1996), multithread (6193 vs 6129), physics (472 vs 428), and find prime numbers (22 vs 19). The 9.3% physics advantage and 13.6% prime number advantage make it the better choice for simulation, finite element analysis, and cryptographic hashing. The 5.1% single-thread lead translates directly to faster response in everyday applications like web browsing, office suites, and light photo editing. For users who run a mix of productivity and creative workloads, the i7-8650U’s consistent edge across Cinebench makes it the more reliable performer.

The Intel Core i5-8350U wins in specific data-processing scenarios. Its 4% lead in extended instructions (5243 vs 5042) and 1.6% lead in random string sorting (10651 vs 10485) make it preferable for database operations, text parsing, and data serialization tasks. The 1.1% wins in data compression (79781 vs 78936) and integer math (22244 vs 22007) favor workloads like file archiving, compression algorithms, and integer-heavy financial calculations. Data encryption is essentially a tie, but the i5 still edges it out at 2075 versus 2067. If a laptop is dedicated to backend data processing, ETL pipelines, or compression-heavy tasks, the i5-8350U offers a measurable throughput benefit. For any other use case, the i7-8650U’s higher clocks and larger cache make it the superior all-rounder, and the 0.7% average benchmark score gap between them is small enough that the i7’s broader wins in standard applications should outweigh the i5’s niche advantages in specialized workloads.