Intel Core i5-7640X vs Intel Core i5-9400T Comparison

The Intel Core i5-7640X and Intel Core i5-9400T represent two very different design philosophies from the same 14 nm process generation. The 7640X is a quad-core, quad-thread Kaby Lake-X part built for the high-end Intel Socket 2066 platform, while the 9400T is a six-core, six-thread Coffee Lake chip with a 35 W TDP designed for the mainstream Intel Socket 1151. Benchmark data shows a split decision: the 9400T wins six of eight head-to-head tests, but the 7640X delivers the two most dramatic victories, particularly in Geekbench. The 9400T’s average benchmark score of 2136 is only 1.4% below the 7640X’s 2167, placing both at the 47th percentile of all CPUs, yet their performance profiles are markedly different across workloads.

The Verdict

The data points to the Intel Core i5-9400T as the more consistent performer in most CPU-bound tasks. It wins every Cinebench test by a margin of about 12.4% to 12.7%, including a 695 vs. 607 score in Cinebench R15 multi-core and a 2896 vs. 2533 in Cinebench R20 multi-core. This is despite the 9400T’s lower 1.80 GHz base clock, because it packs two additional physical cores (six vs. four) and a larger 9 MB shared L3 cache compared to the 7640X’s 6 MB. For users running rendering, encoding, or other heavily threaded workloads, the 9400T is the clear choice based on these results.

However, the Intel Core i5-7640X dominates in Geekbench, with a 50.7% advantage in single-core (1736 vs. 1152) and a 29.4% advantage in multi-core (5137 vs. 3969). This is a substantial reversal that cannot be ignored. The 7640X’s 4.30 GHz boost clock and unlocked multiplier allow it to outperform the 9400T’s 3.40 GHz boost in latency-sensitive and lightly threaded applications. The data suggests the 7640X is better suited for workloads that favor raw clock speed and low thread counts, such as older games or single-threaded productivity tools.

The choice ultimately depends on workload. The 9400T is the safer bet for modern multi-core software, offering a consistent 12.5% lead in Cinebench across all versions. The 7640X is the specialist for high-frequency tasks, with Geekbench single-core scores that are 50.7% higher. The 7640X also benefits from quad-channel memory support and a more expandable platform (Intel Socket 2066), though the 9400T includes integrated UHD 630 graphics, which the 7640X lacks. Given that the 9400T is marked as end-of-life and has a locked multiplier, while the 7640X is unlocked, enthusiasts with overclocking experience may extract more from the 7640X despite its lower stock benchmark results.

FAQ

Q: Which processor has more cores and threads?

A: The Intel Core i5-9400T has six cores and six threads, while the Intel Core i5-7640X has four cores and four threads. The 9400T’s two extra cores contribute to its lead in multi-core Cinebench tests.

Q: Why does the 7640X win Geekbench so decisively despite losing Cinebench?

A: The 7640X wins Geekbench due to its higher 4.30 GHz boost clock and unlocked multiplier. In Geekbench single-core, it scores 1736 vs. 1152 (a 50.7% delta), and in multi-core it scores 5137 vs. 3969 (a 29.4% delta), indicating the benchmark rewards the 7640X’s higher operating frequencies.

Q: What is the TDP difference between the two chips?

A: The Intel Core i5-7640X has a TDP of 112 W, while the Intel Core i5-9400T has a TDP of 35 W. This makes the 9400T far more power-efficient, which is reflected in its lower base clock of 1.80 GHz.

Q: Do both processors support the same memory configuration?

A: No. The 7640X supports quad-channel DDR4 memory, while the 9400T supports dual-channel DDR4. The 9400T has a listed memory bandwidth of 42.7 GB/s, while no bandwidth figure is provided for the 7640X.

Q: Which processor is better for single-threaded performance?

A: Based on Cinebench single-core scores, the 9400T wins by 12.4% to 12.5% in R15, R20, and R23. However, in Geekbench single-core, the 7640X wins by 50.7%. The answer depends on the specific benchmark, but the 7640X’s higher clock speeds give it a decisive edge in Geekbench.

Q: Is the 7640X unlocked for overclocking?

A: Yes, the multiplier is unlocked on the 7640X. The 9400T has a locked multiplier, meaning it cannot be overclocked in the same manner.

Architecture Differences

The two processors are built on the same 14 nm Intel process node, but they belong to different architectural families. The 7640X uses the Kaby Lake architecture, specifically the Kaby Lake-X codename, and is part of the Core i5 X-Series 7th Gen lineup. The 9400T uses the Coffee Lake architecture with the same Coffee Lake codename, part of the Coffee Lake Refresh generation. Both are manufactured by Intel, but their microarchitectural priorities differ.

The most significant architectural split is in core count and cache hierarchy. The 7640X offers four cores and four threads with a shared 6 MB L3 cache, while the 9400T offers six cores and six threads with a shared 9 MB L3 cache. Both have identical L1 and L2 cache sizes per core: 64 KB and 256 KB respectively. The 9400T’s extra 3 MB of L3 cache is a direct consequence of its two additional cores, allowing better data reuse in multi-threaded workloads.

Platform architecture also differs substantially. The 7640X uses the Intel Socket 2066 interface, which is associated with high-end desktop boards and provides quad-channel memory support. The 9400T uses the older Intel Socket 1151 interface with dual-channel memory support. Additionally, the 9400T includes integrated UHD 630 graphics, while the 7640X has no integrated graphics listed. This makes the 9400T a more complete package for systems without a discrete GPU, though the 7640X’s platform offers higher memory bandwidth potential.

The 7640X has an unlocked multiplier, enabling overclocking, whereas the 9400T is locked. The 9400T’s design emphasizes power efficiency with a 35 W TDP, while the 7640X’s 112 W TDP indicates a higher power ceiling for sustained performance. The 9400T is marked as end-of-life, while the 7640X has no production status listed, suggesting different lifecycle stages.

Specification Differences

The table below highlights the key specification differences between the two processors, based only on the data provided.

| Specification | Intel Core i5-7640X | Intel Core i5-9400T |

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

| Cores | 4 | 6 |

| Threads | 4 | 6 |

| Base Clock | 3.90 GHz | 1.80 GHz |

| Boost Clock | 4.30 GHz | 3.40 GHz |

| TDP | 112 W | 35 W |

| Socket | Intel Socket 2066 | Intel Socket 1151 |

| Architecture | Kaby Lake | Coffee Lake |

| Codename | Kaby Lake-X | Coffee Lake |

| Generation | Core i5 (X-Series 7th Gen) | Core i5 (Coffee Lake Refresh) |

| L3 Cache | 6 MB (shared) | 9 MB (shared) |

| Memory Bus | Quad-channel | Dual-channel |

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

| Integrated Graphics | None | UHD 630 |

| Production Status | Not listed | End-of-life |

| Release Date | 2017-06-25 | 2018-08-31 |

| Multiplier Unlocked | Yes | No |

| Part Number | Not listed | SR3X8 |

Head-to-Head Benchmarks

The benchmark results reveal a clear pattern: the 9400T wins all six Cinebench tests, while the 7640X wins both Geekbench tests. The 9400T’s Cinebench victories are consistent, with a delta of -12.7% in R15 multi-core (607 vs. 695) and -12.4% in R15 single-core (85 vs. 97). This trend continues in R20, where the 9400T leads by -12.5% in both multi-core (2533 vs. 2896) and single-core (357 vs. 408). In R23, the margins are identical at -12.5% for multi-core (6031 vs. 6896) and single-core (851 vs. 973).

These Cinebench results indicate that the 9400T’s six cores provide a consistent advantage in rendering workloads, even at lower clock speeds. The 12.5% lead is uniform across all three Cinebench versions, suggesting a stable architectural benefit rather than a benchmark-specific anomaly. The 9400T’s 9 MB L3 cache likely helps in these multi-threaded scenarios, offsetting its lower 1.80 GHz base clock.

The Geekbench results tell the opposite story. The 7640X wins multi-core with a 29.4% delta (5137 vs. 3969) and single-core with a 50.7% delta (1736 vs. 1152). These are the largest margins in the entire head-to-head comparison. The 7640X’s 4.30 GHz boost clock is likely the primary driver, as Geekbench tends to reward higher instantaneous frequencies. The 50.7% single-core lead is particularly striking, showing that the 7640X can nearly double the 9400T’s performance in this specific test.

The win count reflects this split: the 7640X wins 2 tests, while the 9400T wins 6. However, the average benchmark scores are close, with the 7640X at 2167 and the 9400T at 2136, a difference of only 1.4%. This proximity in average score, despite the divergent test results, suggests that the two chips are comparable in overall capability but excel in different workload types. The 7640X’s nearest rivals include the Intel Core i5-1145G7E and AMD Ryzen 5 3400GE, with deltaPct values between -0.3% and 0.4%, while the 9400T’s nearest rivals include the AMD Ryzen 3 5300U and AMD Ryzen 3 3300X, with deltaPct values from -0.6% to 0.6%. Both chips sit in the 47th percentile of all CPUs, underscoring their similar overall standing.