Intel Core i5-12400F vs Intel Core i7-8700K Comparison

The Intel Core i5-12400F is the decisive winner in this comparison, taking 18 of 19 head-to-head benchmarks against the older Intel Core i7-8700K. The data shows a generational leap that the i7-8700K cannot overcome, despite its higher boost clock and unlocked multiplier. The only benchmark where the i7-8700K wins is a narrow victory in PassMark random string sorting, where it scores 25270 against 22975, a 10% margin. Everywhere else, the i5-12400F leads, often by substantial double-digit percentages.

Head-to-Head Benchmarks

The most lopsided result in the entire comparison is in PassMark data encryption, where the i5-12400F scores 11679 against the i7-8700K’s 4776. That is a 59.1% advantage, the largest delta in the dataset. This is not a marginal improvement; it indicates a fundamentally different capability in handling encryption workloads. Similarly, in PassMark find prime numbers, the i5-12400F scores 72 versus 39, a 45.8% lead, showing a major advantage in integer-heavy mathematical operations.

In multi-core rendering, the i5-12400F is consistently ahead. Cinebench R15 multi-core shows 1759 versus 1161, a 34% difference. Cinebench R20 multi-core follows with 6980 versus 4841, a 30.6% gap. The margin narrows in Cinebench R23 multi-core, where the i5-12400F scores 12380 against 11527, a 6.9% lead. This narrowing trend suggests that as the workload scales in complexity, the i7-8700K’s older architecture closes some of the gap, but it still loses. Single-core results follow the same pattern: Cinebench R15 single-core is 244 versus 163 (33.2% ahead), R20 single-core is 985 versus 683 (30.7% ahead), and R23 single-core is 1680 versus 1627 (3.2% ahead).

The i5-12400F also dominates in synthetic system benchmarks. Geekbench multi-core shows 9472 versus 7140, a 24.6% advantage. Geekbench single-core is 1964 versus 1575, a 19.8% lead. PassMark multithread scores 19433 versus 13576, a 30.1% gap, while PassMark single-thread is 3481 versus 2720, a 21.9% lead. In floating-point math, the i5-12400F scores 46759 against 28538, a 39% advantage. Integer math is 59995 versus 45892, a 23.5% lead. PassMark physics shows 1202 versus 811, a 32.5% gap, and PassMark extended instructions shows 15834 versus 13514, a 14.7% lead. Data compression also favors the i5-12400F, with 233327 versus 198951, a 14.7% advantage.

The Verdict

The data is unambiguous. The Intel Core i5-12400F is the superior processor for nearly every task measured. The i7-8700K holds a single victory in random string sorting, but that one win is dwarfed by the scale and consistency of the i5-12400F’s victories elsewhere. The i5-12400F is not just faster; it is dramatically faster in encryption, prime number calculation, and floating-point math.

For a user choosing between these two, the i5-12400F is the clear pick for multi-threaded productivity, content creation, and any workload that leverages modern instruction sets. The i7-8700K, despite being an unlocked part with a 4.70 GHz boost clock, simply cannot match the architectural efficiency of the newer Alder Lake design. The i7-8700K’s only niche, based on this data, is a specific sorting workload where its 10% advantage in random string sorting could matter, but that is a narrow use case. The i5-12400F is also the safer long-term choice because it is an active production part, while the i7-8700K is end-of-life.

Architecture Differences

The two processors come from different architectural eras. The i7-8700K is built on Coffee Lake, a 14 nm process, while the i5-12400F uses Alder Lake on a 10 nm node. This process shrink is a primary driver of the performance gap, allowing the i5-12400F to deliver higher performance at a lower 65 W TDP compared to the i7-8700K’s 95 W TDP. The i5-12400F also uses a newer socket, Intel Socket 1700, versus the older Intel Socket 1151 on the i7-8700K.

Cache configurations differ significantly. The i7-8700K has 64 KB of L1 cache per core and 256 KB of L2 cache per core, with 12 MB of shared L3 cache. The i5-12400F has larger per-core caches: 80 KB of L1 and 1.25 MB of L2, plus a larger 18 MB shared L3 cache. The larger L2 and L3 caches on the i5-12400F help explain its advantage in data-heavy workloads like encryption and compression. The i5-12400F also supports a wider PCIe interface, Gen 5 with 20 lanes, versus Gen 3 with 16 lanes on the i7-8700K.

Memory support also diverges. The i7-8700K supports only DDR4, while the i5-12400F supports both DDR4 and DDR5. The i7-8700K lists a memory bandwidth of 42.7 GB/s, while the i5-12400F’s memory bandwidth is not specified in the data. The i7-8700K includes integrated UHD Graphics 630, while the i5-12400F has no integrated graphics, as indicated by the "F" suffix. The i7-8700K has an unlocked multiplier, allowing overclocking, whereas the i5-12400F is locked.

Specification Differences

| Specification | Intel Core i7-8700K | Intel Core i5-12400F |

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

| Base Clock | 3.70 GHz | 2.50 GHz |

| Boost Clock | 4.70 GHz | 4.40 GHz |

| TDP | 95 W | 65 W |

| Socket | Intel Socket 1151 | Intel Socket 1700 |

| Architecture | Coffee Lake | Alder Lake |

| Process Node | 14 nm | 10 nm |

| L1 Cache | 64 KB (per core) | 80 KB (per core) |

| L2 Cache | 256 KB (per core) | 1.25 MB (per core) |

| L3 Cache | 12 MB (shared) | 18 MB (shared) |

| Memory Support | DDR4 | DDR4, DDR5 |

| Memory Bandwidth | 42.7 GB/s | Not specified |

| PCIe | Gen 3, 16 Lanes (CPU only) | Gen 5, 20 Lanes (CPU only) |

| Integrated Graphics | UHD Graphics 630 | None |

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

| Release Date | 2017-10-04 | 2022-01-03 |

| Launch MSRP | $359 | $174 |

| Multiplier Unlocked | Yes | No |

FAQ

Q: Which processor has a higher boost clock?

A: The Intel Core i7-8700K has a boost clock of 4.70 GHz, while the Intel Core i5-12400F has a boost clock of 4.40 GHz.

Q: Does the i5-12400F support DDR5 memory?

A: Yes, the i5-12400F supports both DDR4 and DDR5, while the i7-8700K only supports DDR4.

Q: Which processor is better for encryption workloads?

A: The i5-12400F is overwhelmingly better, scoring 11679 in PassMark data encryption versus 4776 for the i7-8700K, a 59.1% advantage.

Q: Is the i7-8700K overclockable?

A: Yes, the i7-8700K has an unlocked multiplier, whereas the i5-12400F is locked and does not support overclocking.

Q: Which CPU has a larger L3 cache?

A: The i5-12400F has 18 MB of shared L3 cache, compared to 12 MB on the i7-8700K.

Q: What is the production status of each processor?

A: The i7-8700K is end-of-life, while the i5-12400F is an active production part.

Where Each One Wins

The Intel Core i5-12400F wins in almost every measurable category. It is the correct choice for multi-threaded rendering, as shown by its 30.6% lead in Cinebench R20 multi-core and 34% lead in Cinebench R15 multi-core. It is also the superior choice for single-threaded tasks, with a 19.8% lead in Geekbench single-core and a 21.9% lead in PassMark single-thread. For cryptography and data integrity, the i5-12400F is the only rational option, given its 59.1% lead in encryption and 45.8% lead in prime number finding. For floating-point and integer math, the i5-12400F leads by 39% and 23.5%, respectively. It is also more power-efficient, with a 65 W TDP versus 95 W.

The Intel Core i7-8700K has exactly one win: PassMark random string sorting, where it scores 25270 versus 22975, a 10% advantage. This indicates a specific strength in sorting algorithms that the newer architecture does not replicate. The i7-8700K also retains the advantage of an unlocked multiplier, which is not reflected in the benchmark scores but allows manual overclocking. It also has integrated graphics, which the i5-12400F lacks, making the i7-8700K a fallback option for systems without a discrete GPU. For any user prioritizing sorting-heavy workloads or needing integrated graphics, the i7-8700K has a niche, but for all-round performance, the i5-12400F is the definitive winner.