Intel Core i5-11400F vs Intel Core i7-1255U Comparison

The Intel Core i7-1255U and Intel Core i5-11400F occupy different market segments: the former is a mobile Alder Lake-U processor, the latter a desktop Rocket Lake-S chip. Despite the i7's newer architecture and higher physical core count, head-to-head benchmark data shows the i5-11400F winning 14 of 17 recorded tests, with the i7-1255U taking only three single-threaded wins. This analysis breaks down the measured performance, specification differences, and architectural choices.

Head-to-Head Benchmarks

The i5-11400F dominates the multi-threaded tests. In Cinebench R23 multi-core, the i5 scores 14340 against the i7's 8285, a deficit of 42.2% for the i7. The gap is even larger in Passmark extended instructions, where the i5 leads 14976 to 8231, a 45% margin. Passmark random string sorting shows a 29.8% advantage for the i5 (24124 vs 16934), and Passmark data compression is 29.3% higher on the i5 (208472 vs 147320). Cinebench R20 multi-core gives the i5 a 23% lead (6022 vs 4635), and Passmark multithread is 21.7% higher (16908 vs 13234). Even in Cinebench R15 multi-core, where the i5's margin is smallest, it still wins by 4% (1445 vs 1387).

The i5 also wins in several single-threaded tests. Cinebench R20 single-core shows the i5 at 850 versus 654, a 23.1% lead. Cinebench R23 single-core gives the i5 2024 against 1647, an 18.6% advantage. Passmark integer math, data encryption, physics, and floating point math all favor the i5, with margins of 15.8%, 9.6%, 6.3%, and 4.4% respectively.

The i7-1255U's wins are limited to two distinct tests. In Cinebench R15 single-core, it scores 237.5 versus 204, a 16.4% lead. In Passmark single-thread, it records 3192 against 2981, a 7.1% advantage. The duplicate Passmark singlethread entry shows the same result. These are the only head-to-head victories for the i7.

The overall win count is decisive: 14 for the i5-11400F, 3 for the i7-1255U. The i7's higher core count (10 vs 6) does not translate into multi-threaded superiority in these tests, likely due to the i5's higher base clock (2.60 GHz vs 1.70 GHz) and its desktop power envelope. The i7 does have a higher average benchmark score in the database (17656 vs 17177), but that average is drawn from a broader set of tests and does not reflect the common head-to-head results.

FAQ

Q: Which CPU wins in single-threaded benchmarks?

A: The results are mixed. The i7-1255U leads in Cinebench R15 single-core by 16.4% (237.5 vs 204) and in Passmark single-thread by 7.1% (3192 vs 2981). However, the i5-11400F leads in Cinebench R20 single-core by 23.1% (850 vs 654) and in Cinebench R23 single-core by 18.6% (2024 vs 1647). The i5 is faster in the newer Cinebench versions.

Q: Which CPU has more cores and threads?

A: The i7-1255U has 10 cores and 12 threads, while the i5-11400F has 6 cores and 12 threads. Both have the same thread count, but the i7 has more physical cores.

Q: Does the i7-1255U support DDR5 memory?

A: Yes, the i7-1255U supports both DDR4 and DDR5, while the i5-11400F supports only DDR4.

Q: Which CPU has integrated graphics?

A: The i7-1255U includes Iris Xe 96EU integrated graphics, while the i5-11400F has no integrated graphics.

Q: What are the TDP differences?

A: The i7-1255U has a TDP of 15W, while the i5-11400F has a TDP of 65W. This reflects the i7's mobile design and the i5's desktop orientation.

Q: Which CPU is still in production?

A: The i7-1255U is listed as Active, while the i5-11400F is End-of-life.

The Verdict

Based on the head-to-head data, the i5-11400F is the stronger performer in the majority of tests, winning 14 of 17. It dominates multi-threaded workloads, with margins ranging from 4% in Cinebench R15 multi-core to 45% in Passmark extended instructions. The i7-1255U only wins in two single-threaded tests (Cinebench R15 single-core and Passmark single-thread) and has a higher average benchmark score overall, but that average includes a different set of tests. For desktop users prioritizing multi-threaded performance, the i5-11400F is the clear choice. For mobile or power-constrained systems where integrated graphics and lower TDP are important, the i7-1255U is the appropriate option. The i5-11400F is end-of-life, while the i7-1255U remains active.

Specification Differences

| Specification | Intel Core i7-1255U | Intel Core i5-11400F |

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

| Cores | 10 | 6 |

| Base Clock | 1.70 GHz | 2.60 GHz |

| Boost Clock | 4.70 GHz | 4.40 GHz |

| TDP | 15 W | 65 W |

| Socket | Intel BGA 1744 | Intel Socket 1200 |

| Architecture | Alder Lake | Rocket Lake |

| Codename | Alder Lake-U | Rocket Lake |

| Generation | Core i7 (Alder Lake-U) | Core i5 (Rocket Lake-S) |

| Process Node | 10 nm | 14 nm |

| Die Size | Not listed | 276 mm² |

| L2 Cache | 1.25 MB (per core) | 512 KB (per core) |

| Memory Support | DDR4, DDR5 | DDR4 |

| Memory Bandwidth | Not listed | 51.2 GB/s |

| Integrated Graphics | Iris Xe 96EU | None |

| Market Segment | Mobile | Desktop |

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

| Release Date | 2022-02-22 | 2021-03-15 |

| Launch MSRP | Not listed | $157 |

| Part Number | SRLFP | SRKP1 |

Architecture Differences

The i7-1255U is built on Intel's Alder Lake-U architecture using a 10 nm process, while the i5-11400F uses the Rocket Lake architecture on a 14 nm node. The i7 has 10 cores and 12 threads, compared to 6 cores and 12 threads for the i5. The i7's L2 cache is larger at 1.25 MB per core versus 512 KB per core, but both share 12 MB of L3 cache. The i7 supports both DDR4 and DDR5 memory, while the i5 is limited to DDR4. The i7 includes integrated Iris Xe 96EU graphics, whereas the i5 has no integrated graphics. The i7 has a lower base clock (1.70 GHz) but a higher boost clock (4.70 GHz) than the i5 (2.60 GHz base, 4.40 GHz boost). The i7 is a mobile part with a 15W TDP, while the i5 is a desktop part with a 65W TDP. The i7 uses the BGA 1744 socket, the i5 uses Socket 1200. The i7 was released later (2022-02-22) and remains active, while the i5 (released 2021-03-15) is end-of-life. The i5 has a listed die size of 276 mm²; the i7's die size is not recorded.