CPU Comparison

The Intel Core i5-9400F and Intel Core i5-8400 are two six-core, six-thread desktop processors built on the same Coffee Lake architecture and 14 nm process. Both are end-of-life products aimed at the mainstream desktop segment, but the 9400F is a refresh that arrives with a slightly higher clock speed and a notable omission: integrated graphics. Benchmark data shows a consistent, if modest, performance edge for the newer 9400F across nearly every workload, though the 8400 retains one narrow victory that keeps the comparison from being a total shutout.

Head-to-Head Benchmarks

The most striking pattern in the head-to-head data is the sheer consistency of the 9400F’s advantage. Out of 19 benchmark comparisons, the 9400F wins 18, with margins that cluster tightly in the 2% to 3% range. In Cinebench R23 multi-core, the 9400F scores 8040 against the 8400’s 7847, a 2.5% lead. The single-core result tells the same story: 1135 versus 1107, also 2.5% ahead. This uniformity suggests the performance gap is not workload-specific but rather a direct consequence of clock speed.

The largest deltas appear in Cinebench R15 single-core and PassMark data encryption, where the 9400F leads by 2.7% and 2.8%, respectively. In PassMark physics, the 9400F scores 653 versus 635, a 2.8% margin that is the biggest win of the entire suite. Integer math follows with 26155 versus 25573, a 2.3% gap, while floating-point math shows 22465 against 22006, a 2.1% difference. Even data compression, which often favors architectural efficiency, goes to the 9400F at 132877 versus 129951, a 2.3% edge.

The 8400’s lone victory comes in Geekbench single-core, where it scores 1353 against the 9400F’s 1344, a 0.7% margin. This is an outlier in an otherwise uniform picture, and it is worth noting that the 9400F still wins Geekbench multi-core with 5106 versus 5088, albeit by a slim 0.4%. The multi-core Geekbench result is the smallest margin of any 9400F win, suggesting that the newer chip’s advantage shrinks in certain synthetic workloads that may not scale purely with clock speed.

In aggregate, the 9400F’s average benchmark score is 13041, while the 8400 sits at 12765, a difference of roughly 2.2%. Both processors land in the 68th percentile of all CPUs, placing them in the same performance tier. The 9400F’s nearest rivals include the Intel Core i7-10750H (0.1% ahead) and the Core Ultra 3 105UL (0.1% behind), while the 8400’s closest competitor is the Xeon Gold 6348, which is 0.2% ahead. These rival deltas are tiny, underscoring that both chips are firmly mid-pack performers in the broader CPU landscape.

FAQ

Q: How much faster is the Intel Core i5-9400F than the i5-8400 in multi-core workloads?

A: Across Cinebench R15, R20, and R23 multi-core tests, the 9400F leads by 2.5% in each case. In PassMark multithread, the gap is also 2.5%, with scores of 9455 versus 9225.

Q: Does the i5-8400 win any benchmark against the 9400F?

A: Yes, in Geekbench single-core the 8400 scores 1353 against the 9400F’s 1344, a 0.7% advantage. This is the only one of 19 head-to-head tests that the 8400 wins.

Q: What is the biggest performance difference between the two chips?

A: The largest margins are 2.8% in PassMark data encryption and PassMark physics, where the 9400F scores 2902 versus 2824 and 653 versus 635, respectively.

Q: Are these processors in the same performance percentile?

A: Yes, both are in the 68th percentile of all CPUs, and their average benchmark scores are 13041 for the 9400F and 12765 for the 8400.

Q: Do both chips support the same memory configuration?

A: Yes, both support DDR4 memory in dual-channel mode with a memory bandwidth of 42.7 GB/s.

Q: Which chip has a higher boost clock?

A: The 9400F has a boost clock of 4.10 GHz, while the 8400 boosts to 4.00 GHz.

Architecture Differences

Both processors are built on Intel’s Coffee Lake architecture using a 14 nm process node, and they share the same core configuration: 6 cores and 6 threads. The cache hierarchy is identical, with 64 KB of L1 per core, 256 KB of L2 per core, and 9 MB of shared L3 cache. Neither chip supports ECC memory, and both use the Intel Socket 1151. The memory controller is the same, offering dual-channel DDR4 support with 42.7 GB/s bandwidth.

The critical architectural divergence is the integrated graphics. The i5-8400 includes UHD Graphics 630, while the 9400F has no integrated graphics at all, as indicated by the "F" suffix in its name. This means the 9400F requires a discrete GPU for any display output, whereas the 8400 can operate with just the CPU’s iGPU. The die size also differs, with the 8400 measuring 154 mm², while the 9400F’s die size is not listed in the data.

The generation labels differ as well. The 9400F is part of the Core i5 (Coffee Lake Refresh) generation, while the 8400 belongs to the original Core i5 (Coffee Lake) generation. This refresh designation explains the clock speed bump: the 9400F runs at a base clock of 2.90 GHz versus 2.80 GHz for the 8400, and boosts to 4.10 GHz versus 4.00 GHz. The 9400F was released on 2019-01-07, while the 8400 came earlier on 2017-10-04.

Specification Differences

The two processors differ in several key specifications, all of which stem from the 9400F’s status as a refresh. The base clock is 2.90 GHz on the 9400F versus 2.80 GHz on the 8400, a 100 MHz difference. Boost clocks follow the same pattern, with the 9400F reaching 4.10 GHz and the 8400 topping out at 4.00 GHz.

The most significant specification gap is the absence of integrated graphics on the 9400F. The 8400 ships with UHD Graphics 630, while the 9400F has none. This is a functional difference that affects system requirements: the 9400F mandates a discrete GPU, while the 8400 can run headless or with a basic display adapter.

The die size is another differentiator, with the 8400 listed at 154 mm² and the 9400F having no value provided. The part numbers also differ, with the 9400F carrying the long identifier "BX80684I59400FBXC80684I59400FCM8068403358819SRF6M" and the 8400 using the shorter "SLAPL". The release dates are distinct, with the 9400F launching on 2019-01-07 and the 8400 on 2017-10-04.

Notably, the launch MSRP field is only populated for the 8400, which carries a launch MSRP of $182. The 9400F has no launch MSRP listed. Both processors share the same TDP of 65 watts, the same PCIe configuration of Gen 3 with 16 lanes (CPU only), and both are locked (multiplier unlocked: false). The 8400’s generation is listed as "Core i5 (Coffee Lake)" while the 9400F’s is "Core i5 (Coffee Lake Refresh)."

The Verdict

The data presents a clear, if narrow, case for the Intel Core i5-9400F. It wins 18 of 19 head-to-head benchmarks, with typical margins of 2.1% to 2.8%, and its average benchmark score of 13041 is 276 points higher than the 8400’s 12765. The consistent edge across Cinebench, PassMark, and Geekbench multi-core tests indicates that the 9400F’s higher base and boost clocks translate directly into real-world performance gains. For anyone building a system with a discrete GPU, the 9400F is the superior choice on raw performance alone.

However, the 8400 is not without merit. Its integrated UHD Graphics 630 means it can function without a separate graphics card, which is a decisive factor for budget systems or office builds where a GPU is unnecessary. The 8400 also wins Geekbench single-core by 0.7%, though this is a minor consolation. Its earlier release date and listed launch MSRP of $182 provide historical context, but neither affects current performance.

For a user who already owns a dedicated GPU, the 9400F is the pick. The 2.5% average lead in multi-core workloads is meaningful for CPU-bound tasks like video encoding or 3D rendering. For a user who needs an all-in-one solution without a discrete graphics card, the 8400 is the only viable option of the two, as the 9400F cannot output video on its own. In that scenario, the 8400’s 0.7% single-core win and integrated graphics make it the logical choice, despite its overall performance deficit.