Intel Core i3-7350K vs Intel Core i7-8665U Comparison

Where Each One Wins

The benchmark data presents an unusually one-sided picture. Across all six head-to-head Cinebench tests, the Intel Core i7-8665U wins outright. There is no test in the recorded database where the Intel Core i3-7350K takes the lead. The i7-8665U dominates in both single-core and multi-core workloads, making the use-case split less about workload type and more about platform context.

The i7-8665U is a mobile processor, built for thin-and-light laptops, while the i3-7350K is a desktop part aimed at entry-level fixed systems. The mobile chip wins in every recorded benchmark, but the desktop chip has its own appeal in a different context. The i3-7350K offers a 4.20 GHz base clock with no boost clock listed, meaning it runs at a constant high frequency. The i7-8665U has a 1.90 GHz base clock that boosts to 4.80 GHz, a far wider frequency envelope. For sustained all-core workloads, the i7-8665U still comes out ahead according to the data, but the i3-7350K's steady clock could be preferable in scenarios where frequency consistency matters more than peak throughput.

The i3-7350K also has an unlocked multiplier, which the i7-8665U lacks. That means the desktop chip can be overclocked, though the database does not record any overclocked benchmark results. At stock settings, the i7-8665U wins everywhere. The i3-7350K's advantage is purely qualitative: it belongs to a desktop platform with an unlocked multiplier, and it remains in active production, while the i7-8665U is end-of-life.

Architecture Differences

Both processors are built on Intel's 14 nm process node, but they come from different architectural families. The i7-8665U uses Whiskey Lake, specifically the Whiskey Lake-U codename, while the i3-7350K uses Kaby Lake. The generation labels differ too: the i7-8665U is listed as Core i7 (Whiskey Lake), and the i3-7350K is Core i3 (Kaby Lake).

Core counts separate them clearly. The i7-8665U has 4 cores and 8 threads, while the i3-7350K has 2 cores and 4 threads. The i7-8665U therefore doubles the thread count of the i3-7350K. Cache hierarchies also differ. Both share the same per-core L1 and L2 cache sizes at 64 KB and 256 KB per core respectively, but the shared L3 cache is 8 MB on the i7-8665U versus 4 MB on the i3-7350K. That is a full 4 MB difference in favor of the mobile part.

Memory support shows a modest split. The i7-8665U supports both DDR3 and DDR4 memory, while the i3-7350K supports DDR4 only. Both run dual-channel memory with identical 38.4 GB/s bandwidth. Neither supports ECC memory. PCIe configuration is the same on paper: Gen 3 with 16 lanes from the CPU.

Integrated graphics differ. The i7-8665U carries UHD Graphics 620, while the i3-7350K has Intel HD 630. The database does not record graphics benchmark scores for either, so no performance comparison is possible from the recorded data.

The sockets are incompatible. The i7-8665U uses Intel BGA 1528, a soldered mobile socket, while the i3-7350K uses Intel Socket 1151, a desktop LGA socket. This means the two processors cannot be swapped between platforms. The i7-8665U is a mobile part with a 15 W TDP, while the i3-7350K is a desktop part with a 60 W TDP. The TDP difference is substantial, reflecting the mobile chip's power efficiency mandate versus the desktop chip's higher power envelope.

Production status differs as well. The i7-8665U is end-of-life, while the i3-7350K is still active. The i7-8665U launched on 2018-09-30, and the i3-7350K launched on 2017-01-02. The i7-8665U has a launch MSRP of $409. The i3-7350K has no launch MSRP recorded in the database.

Head-to-Head Benchmarks

The six recorded head-to-head tests all come from the Cinebench suite, spanning R15, R20, and R23. The i7-8665U wins every test with a remarkably consistent margin, ranging from 26.1% to 27.6%.

In Cinebench R15 multi-core, the i7-8665U scores 527 against the i3-7350K's 417, a 26.4% lead. The single-core R15 test shows an even larger gap: 74 versus 58, a 27.6% difference. That is the largest margin of any recorded test, suggesting the i7-8665U's boost behavior gives it a particularly strong single-thread advantage in the older R15 workload.

Moving to Cinebench R20, the multi-core test has the i7-8665U at 2197 and the i3-7350K at 1740, a 26.3% delta. The single-core R20 test shows 309 versus 245, a 26.1% delta. These margins are nearly identical to the R15 results, indicating that the performance gap is consistent across Cinebench generations.

Cinebench R23 repeats the pattern. Multi-core: 5232 versus 4144, a 26.3% delta. Single-core: 738 versus 585, a 26.2% delta. The consistency is striking. The i7-8665U leads by roughly 26% across the board, regardless of whether the workload is single-threaded or multi-threaded.

For context, the i7-8665U's average benchmark score is 1513, placing it at the 38th percentile of all CPUs in the database. The i3-7350K's average benchmark score is 1462, also at the 38th percentile. Despite the i7-8665U winning every head-to-head test, the two chips sit at the same percentile ranking. That is a useful reminder that percentile rankings reflect the broader CPU landscape, not just this pairing.

The i7-8665U's nearest rivals include the Intel Pentium Gold G7400E at 1524 (-0.7%), the Intel Core i5-4670S at 1526 (-0.9%), and the Intel Core i5-7440HQ at 1527 (-0.9%). The i3-7350K's nearest rivals include the AMD Ryzen 3 PRO 2200GE at 1461 (0.1%), the Intel Xeon E3-1225 v5 at 1465 (-0.2%), and the Intel Xeon E3-1515M v5 at 1456 (0.4%). Both chips cluster with similarly scoring parts, but the i7-8665U sits slightly higher in absolute average score.

FAQ

Q: Which processor has more cores and threads?

A: The Intel Core i7-8665U has 4 cores and 8 threads, while the Intel Core i3-7350K has 2 cores and 4 threads. The i7-8665U doubles the thread count.

Q: How much faster is the i7-8665U in multi-core workloads?

A: In Cinebench R23 multi-core, the i7-8665U scores 5232 versus 4144 for the i3-7350K, a 26.3% lead. The R20 multi-core test shows a 26.3% lead as well, with scores of 2197 and 1740.

Q: Does the i3-7350K win any benchmark?

A: No. Across all six recorded head-to-head Cinebench tests, the i7-8665U wins every one. The i3-7350K has no recorded wins in this pairing.

Q: What is the single-core performance difference?

A: The largest margin is in Cinebench R15 single-core, where the i7-8665U scores 74 against 58 for the i3-7350K, a 27.6% advantage. R20 single-core shows a 26.1% lead, and R23 single-core shows a 26.2% lead.

Q: Are these processors compatible with the same motherboard?

A: No. The i7-8665U uses Intel BGA 1528, a mobile socket, while the i3-7350K uses Intel Socket 1151, a desktop socket. They cannot be interchanged.

Q: What is the TDP of each processor?

A: The i7-8665U has a 15 W TDP, while the i3-7350K has a 60 W TDP. The mobile part is rated for significantly lower power consumption.

The Verdict

The data points to a clear conclusion: the Intel Core i7-8665U outperforms the Intel Core i3-7350K in every recorded benchmark. The mobile chip leads by roughly 26% across all Cinebench tests, both single-core and multi-core. The consistency of that margin suggests an architectural and core-count advantage that the desktop chip cannot overcome at stock settings.

The i7-8665U should be the pick for anyone prioritizing raw benchmark performance within this pairing. It offers double the threads, double the L3 cache, and a higher boost clock of 4.80 GHz. It also includes newer integrated graphics in the form of UHD Graphics 620. The 15 W TDP makes it suitable for power-constrained mobile designs.

The i3-7350K, however, retains appeal for a different audience. It is a desktop processor with an unlocked multiplier, meaning it can be overclocked. It runs at a constant 4.20 GHz base clock with no boost variability. It remains in active production, while the i7-8665U is end-of-life. For someone building a new desktop system today, the i3-7350K's active production status and unlocked multiplier are meaningful considerations, even if the recorded stock benchmarks favor the mobile chip.

The average benchmark scores tell a similar story. The i7-8665U averages 1513, the i3-7350K averages 1462. Both sit at the 38th percentile of all CPUs, indicating they occupy the same general performance tier in the broader market. But within this specific comparison, the i7-8665U is the faster part.

Specification Differences

| Specification | Intel Core i7-8665U | Intel Core i3-7350K |

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

| Cores | 4 | 2 |

| Threads | 8 | 4 |

| Base Clock | 1900.00 MHz | 4.20 GHz |

| Boost Clock | 4.80 GHz | None |

| TDP | 15 W | 60 W |

| Socket | Intel BGA 1528 | Intel Socket 1151 |

| Architecture | Whiskey Lake | Kaby Lake |

| Codename | Whiskey Lake-U | Kaby Lake |

| Generation | Core i7 (Whiskey Lake) | Core i3 (Kaby Lake) |

| Process Node | 14 nm | 14 nm |

| L3 Cache | 8 MB (shared) | 4 MB (shared) |

| Memory Support | DDR3, DDR4 | DDR4 |

| Integrated Graphics | UHD Graphics 620 | Intel HD 630 |

| Market Segment | Mobile | Desktop |

| Production Status | End-of-life | Active |

| Release Date | 2018-09-30 | 2017-01-02 |

| Launch MSRP | $409 | None |

| Multiplier Unlocked | No | Yes |

| Part Number | SRF9W | SR35B |

Both processors share the same 14 nm process node, 64 KB L1 cache per core, 256 KB L2 cache per core, dual-channel memory bus, 38.4 GB/s memory bandwidth, no ECC support, and Gen 3 PCIe with 16 CPU lanes. The differences are concentrated in core count, clock behavior, cache size, socket, graphics, TDP, production status, and unlock status.