Intel Core i5-8400H vs Intel Core i7-7920HQ Comparison

The Intel Core i5-8400H and Intel Core i7-7920HQ are both 45-watt, 4-core mobile processors aimed at performance laptops, but they come from different Intel generations. The data shows a clear split: the i5-8400H dominates in Cinebench workloads, while the older i7-7920HQ takes a decisive victory in Geekbench multi-core testing. With the i5-8400H winning 7 out of 8 head-to-head benchmark comparisons, the results reveal a nuanced picture where architectural age and cache configuration matter as much as core counts.

Head-to-Head Benchmarks

The most striking result in the dataset is the Geekbench multi-core test, which is the only benchmark where the Intel Core i7-7920HQ comes out ahead. The i7-7920HQ scores 3999, beating the i5-8400H’s 3656 by a substantial 8.6% margin. This is a significant reversal given the i5-8400H’s dominance elsewhere, and it suggests that the older Kaby Lake chip handles certain multi-threaded workloads differently, likely due to its higher base clock of 3.10 GHz compared to the i5-8400H’s 2.50 GHz.

Every other benchmark in the head-to-head comparison favors the Intel Core i5-8400H. In Cinebench R15 multi-core, the i5-8400H scores 644 against the i7-7920HQ’s 619, a 4% advantage. The single-core result in the same test shows 90 versus 87, giving the i5-8400H a 3.4% edge. These margins are consistent across the Cinebench suite: R20 multi-core shows 2684 versus 2583 (3.9%), R20 single-core shows 378 versus 364 (3.8%), R23 multi-core shows 6392 versus 6151 (3.9%), and R23 single-core shows 902 versus 868 (3.9%).

The single-core performance gap is worth emphasizing. The i5-8400H’s boost clock matches the i7-7920HQ at 4.10 GHz, yet the newer Coffee Lake architecture delivers higher scores across all single-threaded Cinebench tests. In Cinebench R23 single-core, the i5-8400H’s 902 points represents a 3.9% improvement over the i7-7920HQ’s 868. Even the Geekbench single-core test, which the i5-8400H wins by a narrower 1.1% margin (1281 versus 1267), confirms that the newer chip has better instruction-level efficiency per clock.

Looking at average benchmark scores, the i5-8400H posts 2003 versus the i7-7920HQ’s 1992, a difference of only 0.5%. This near-parity in the aggregate metric masks the divergent workload behavior. The i5-8400H’s percentile rank of 45 versus the i7-7920HQ’s 44 places both in the lower-middle of all CPUs, but the i5-8400H’s nearest rival is the AMD Ryzen 7 2800H with an average score of 2002 (a 0.1% delta), while the i7-7920HQ sits alongside the AMD Ryzen 5 1500X at 1992 (a 0% delta).

Where Each One Wins

The Intel Core i5-8400H is the clear choice for Cinebench-style rendering workloads. Its 4% lead in Cinebench R15 multi-core and consistent 3.9% margins in R20 and R23 multi-core tests indicate that the newer architecture extracts more performance from the same 4-core, 8-thread configuration. This advantage extends to single-threaded tasks, where the i5-8400H wins every single-core benchmark by margins ranging from 1.1% to 3.9%.

The Intel Core i7-7920HQ finds its strength in the Geekbench multi-core test, where its 8.6% lead over the i5-8400H is the largest margin in either direction across all benchmarks. This suggests that certain multi-threaded workloads that stress memory access patterns or rely on higher sustained base clocks will favor the older chip. The i7-7920HQ’s dual-channel memory bus and support for both DDR3 and DDR4 memory, compared to the i5-8400H’s DDR4-only support, may contribute to this result in memory-sensitive applications.

For everyday single-threaded responsiveness, the i5-8400H’s wins in Geekbench single-core (1281 versus 1267) and all Cinebench single-core tests make it the more consistent performer in lightly-threaded applications. The i7-7920HQ’s only victory, while impressive at 8.6%, appears to be an outlier relative to the overall benchmark pattern, where the i5-8400H wins by smaller but more frequent margins.

Architecture Differences

The fundamental architectural split is Coffee Lake versus Kaby Lake. The Intel Core i5-8400H uses the Coffee Lake-H codename with a 14 nm process node, while the Intel Core i7-7920HQ uses the Kaby Lake-H codename, also on a 14 nm node. Both chips are built by Intel with a 126 mm² die size, indicating similar physical dimensions despite the generational difference.

The most significant architectural difference lies in the L3 cache. The i5-8400H offers 12 MB of shared L3 cache, while the i7-7920HQ provides only 8 MB. This 50% increase in cache capacity for the newer chip likely explains its superior Cinebench performance, as rendering workloads benefit from larger working sets being held in cache. Both chips share the same per-core L1 cache at 64 KB and per-core L2 cache at 256 KB.

Integrated graphics also differ between the two. The i5-8400H features the UHD 630, while the i7-7920HQ uses Intel HD Graphics 630. The UHD 630 represents the newer naming and presumably updated graphics IP, though benchmark data for graphics performance is not provided. Both are integrated solutions for mobile platforms, with no discrete GPU data available.

The i7-7920HQ also supports a broader memory range with DDR3 and DDR4, while the i5-8400H is limited to DDR4. The i7-7920HQ specifies a dual-channel memory bus and PCIe Gen 3 with 16 lanes (CPU only), whereas the i5-8400H’s PCIe configuration is not specified in the data. Neither chip supports ECC memory, and both are locked (multiplier not unlocked).

Specification Differences

The two processors share identical core and thread counts: 4 cores and 8 threads. The TDP is the same at 45 watts, and both use the Intel BGA 1440 socket, making them physically interchangeable in compatible laptops. The process node matches at 14 nm, and both are end-of-life products.

The base clock is where the i7-7920HQ holds a clear advantage: 3.10 GHz versus the i5-8400H’s 2.50 GHz. This 0.60 GHz difference explains the Geekbench multi-core victory for the older chip, as sustained multi-threaded workloads benefit from a higher minimum clock. The boost clock is identical at 4.10 GHz for both, meaning peak single-thread performance potential is the same, though the i5-8400H realizes it better in practice.

The L3 cache difference is the other major spec divergence: 12 MB for the i5-8400H versus 8 MB for the i7-7920HQ. Memory support differs as noted, with the i5-8400H accepting only DDR4 while the i7-7920HQ accepts DDR3 and DDR4, and the i7-7920HQ explicitly lists a dual-channel memory bus.

Release dates and part numbers also differ. The i7-7920HQ launched on 2017-01-02 with a launch MSRP of $568, while the i5-8400H launched on 2018-04-01 with no launch MSRP listed. The part numbers are SR32L for the i7-7920HQ and SR3Z1 for the i5-8400H.

FAQ

Q: Which processor is faster in Cinebench R23 multi-core?

A: The Intel Core i5-8400H scores 6392 in Cinebench R23 multi-core, beating the Intel Core i7-7920HQ’s 6151 by 3.9%.

Q: How much larger is the L3 cache on the i5-8400H?

A: The i5-8400H has 12 MB of shared L3 cache, while the i7-7920HQ has 8 MB, a 4 MB difference in favor of the newer chip.

Q: What is the only benchmark where the i7-7920HQ wins?

A: The i7-7920HQ wins the Geekbench multi-core test with a score of 3999, beating the i5-8400H’s 3656 by 8.6%.

Q: Do both processors have the same core count and TDP?

A: Yes, both have 4 cores and 8 threads with a 45-watt TDP, and both use the Intel BGA 1440 socket.

Q: What is the base clock difference between the two?

A: The i7-7920HQ has a base clock of 3.10 GHz, which is 0.60 GHz higher than the i5-8400H’s 2.50 GHz base clock.

Q: Which processor supports DDR3 memory?

A: Only the i7-7920HQ supports DDR3 and DDR4 memory; the i5-8400H supports DDR4 exclusively.