Intel Core i3-10305 vs Intel Core i5-9400 Comparison

The Intel Core i3-10305 and Intel Core i5-9400 are both 14 nm desktop parts from Intel, but they represent different design philosophies from different eras. The data reveals a clear generational shift: the newer i3-10305, despite having fewer physical cores, wins every single benchmark in the head-to-head comparison. The i5-9400 counters with more cores and slightly more cache, yet the benchmark scores show that the i3-10305’s higher clock speeds and simultaneous multithreading (SMT) more than compensate. This is a fascinating case of architectural efficiency versus raw core count.

Where Each One Wins

The benchmark results present an unambiguous picture: the Intel Core i3-10305 wins in every tested workload. There are zero wins for the Intel Core i5-9400 across the six head-to-head Cinebench tests. This means that in both single-threaded and multi-threaded scenarios, the i3-10305 comes out ahead. The i3-10305’s dominance is consistent, with deltas of roughly 18% across all tests, indicating a uniform performance advantage rather than a workload-specific one.

For the i5-9400, its theoretical advantage lies in its core count—6 physical cores versus 4—which might suggest better multi-threading potential. However, the data shows this does not translate into a win. The i3-10305’s 8 threads (thanks to Hyper-Threading) outperform the i5-9400’s 6 threads in multi-core Cinebench tests. The i5-9400 does have a larger L3 cache (9 MB shared vs. 8 MB shared), but this advantage is insufficient to overcome the clock speed deficit and lack of SMT. In real-world terms, the i3-10305 is the better choice for both lightly-threaded tasks like gaming and heavily-threaded tasks like rendering, based strictly on these numbers.

Architecture Differences

The two processors come from different architectural families and sockets. The Intel Core i3-10305 is based on Comet Lake, specifically the Comet Lake-R update, and uses the Intel Socket 1200. The Intel Core i5-9400 is based on the older Coffee Lake architecture (Coffee Lake Refresh) and uses the Intel Socket 1151. This socket difference is critical for platform compatibility, as the two CPUs are not interchangeable on the same motherboard.

Both chips are manufactured on Intel’s 14 nm process node and share the same foundry, but their core configurations differ significantly. The i3-10305 has 4 cores and 8 threads, while the i5-9400 has 6 cores and 6 threads. The lack of Hyper-Threading on the i5-9400 is a notable feature omission. Clock speeds also differ: the i3-10305 has a base clock of 3.80 GHz and a boost clock of 4.50 GHz, while the i5-9400 runs at a lower 2.90 GHz base and 4.10 GHz boost. This clock advantage is a major factor in the i3-10305’s performance lead.

Cache hierarchies are similar in structure—both have 64 KB L1 and 256 KB L2 per core—but differ in L3, with the i5-9400 offering 9 MB shared versus 8 MB shared on the i3-10305. Both support dual-channel DDR4 memory with identical memory bandwidth of 42.7 GB/s, and both lack ECC support. Integrated graphics are also identical (UHD 630 for the i3-10305, UHD 630 for the i5-9400). The i3-10305 is listed as Active in production, while the i5-9400 is End-of-life, and their release dates are far apart: March 2021 for the i3-10305 and October 2018 for the i5-9400.

Head-to-Head Benchmarks

The Cinebench results show a remarkably consistent performance gap. In Cinebench R15 multi-core, the i3-10305 scores 788 versus the i5-9400’s 668, a lead of 18%. The single-core R15 test shows a similar story: 111 for the i3-10305 versus 94 for the i5-9400, a delta of 18.1%. Moving to Cinebench R20, the multi-core score is 3287 for the i3-10305 and 2784 for the i5-9400, again an 18.1% difference. The R20 single-core test shows the i3-10305 at 464 and the i5-9400 at 392, a delta of 18.4%.

The pattern holds in the latest Cinebench R23. In multi-core, the i3-10305 scores 7828 versus 6629 for the i5-9400, an 18.1% advantage. In single-core, the scores are 1105 and 935 respectively, a delta of 18.2%. These numbers are striking because they are so uniform. The i3-10305’s advantage is not a fluke of one test; it is a systematic lead across all rendering workloads. This consistency suggests that the higher clocks and SMT provide a fundamental throughput advantage that the i5-9400’s two extra physical cores cannot overcome.

It is also worth noting the average benchmark score context. The i3-10305 has an average benchmark score of 2264, while the i5-9400 sits at 2254, a negligible 0.4% difference in aggregate. However, this aggregate similarity masks the fact that the i5-9400’s data set includes Geekbench scores (5141 multi-core, 1389 single-core), which are not present for the i3-10305. The Cinebench-specific head-to-head data is where the i3-10305’s dominance is clearly demonstrated.

The Verdict

Based solely on the data provided, the Intel Core i3-10305 is the superior processor in every measured category. It wins all six head-to-head Cinebench benchmarks with deltas of approximately 18%. For users who prioritize raw performance in both single-threaded and multi-threaded applications, the i3-10305 is the clear choice. Its higher clock speeds (3.80 GHz base, 4.50 GHz boost) and 8 threads provide a decisive advantage over the i5-9400’s 6 threads and lower clocks (2.90 GHz base, 4.10 GHz boost).

The i5-9400’s only advantages are its 6 physical cores and 9 MB of L3 cache, but these do not translate to any benchmark wins. The data suggests that SMT on the i3-10305 effectively compensates for the two missing physical cores. Furthermore, the i3-10305 is an Active product with a newer release date (March 2021), whereas the i5-9400 is End-of-life (released October 2018). Platform considerations aside—the i3-10305 requires Socket 1200, the i5-9400 uses Socket 1151—the performance data is one-sided. Users building a new system should favor the i3-10305 based on these benchmark results, while those already on a Socket 1151 platform might consider the i5-9400 for an upgrade, but the data shows they would be sacrificing performance.

FAQ

Q: Which CPU has more cores?

A: The Intel Core i5-9400 has 6 physical cores, while the Intel Core i3-10305 has 4 physical cores.

Q: Does the i3-10305 have an advantage in multi-threaded workloads?

A: Yes. Despite having fewer cores, the i3-10305 has 8 threads thanks to Hyper-Threading, and it wins all multi-core Cinebench tests by about 18% over the i5-9400.

Q: What is the difference in clock speeds?

A: The i3-10305 has a base clock of 3.80 GHz and a boost clock of 4.50 GHz, while the i5-9400 has a base clock of 2.90 GHz and a boost clock of 4.10 GHz.

Q: Are these CPUs compatible with the same motherboard?

A: No. The i3-10305 uses Intel Socket 1200, while the i5-9400 uses Intel Socket 1151.

Q: Which CPU has a larger L3 cache?

A: The i5-9400 has a larger L3 cache at 9 MB shared, compared to 8 MB shared on the i3-10305.

Q: What are the average benchmark scores for each CPU?

A: The i3-10305 has an average benchmark score of 2264, and the i5-9400 has an average score of 2254.

Specification Differences

| Specification | Intel Core i3-10305 | Intel Core i5-9400 |

|:--- |:--- |:--- |

| Cores | 4 | 6 |

| Threads | 8 | 6 |

| Base Clock | 3.80 GHz | 2.90 GHz |

| Boost Clock | 4.50 GHz | 4.10 GHz |

| Socket | Intel Socket 1200 | Intel Socket 1151 |

| Architecture | Comet Lake | Coffee Lake |

| Codename | Comet Lake-R | Coffee Lake |

| L3 Cache | 8 MB (shared) | 9 MB (shared) |

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

| Release Date | 2021-03-15 | 2018-10-18 |

| Part Number | SRH3K | SR3X5 |