AMD Ryzen 5 7640U vs AMD Ryzen 7 7840U Comparison

Both AMD Ryzen 7000-series mobile processors share the same Zen 4 architecture, 4nm TSMC process node, and 25,000 million transistors on a 178 mm² die, yet benchmark results show they are not interchangeable. The Ryzen 5 7640U and Ryzen 7 7840U are positioned for different workloads, with the data revealing a clear split between single-threaded responsiveness and raw multi-threaded throughput.

FAQ

Q: Which processor has a higher average benchmark score?

A: The AMD Ryzen 5 7640U has an average benchmark score of 25485, which is 0.2% higher than the Ryzen 7 7840U's average score of 25432. This places the Ryzen 5 in the 78th percentile of all CPUs, while the Ryzen 7 sits in the 77th percentile.

Q: How do the two processors compare in Cinebench R23 multi-core performance?

A: The Ryzen 5 7640U wins decisively with a score of 17936, which is 41% ahead of the Ryzen 7 7840U's 12719. This is a surprising result given the Ryzen 7 has two additional physical cores.

Q: What is the difference in single-core performance between the two?

A: In Cinebench R23 single-core tests, the Ryzen 5 7640U scores 2532, which is 50.9% higher than the Ryzen 7 7840U's 1677.5. The Ryzen 5 also edges ahead in Geekbench single-core with 2127 versus 2077, a 2.4% margin.

Q: Which processor handles data compression and encryption workloads better?

A: The Ryzen 7 7840U leads in both areas. It scores 288604 in Passmark data compression (16.8% higher) and 17691 in data encryption (15.5% higher) compared to the Ryzen 5 7640U's scores of 240032 and 14954, respectively.

Q: Are there any benchmark categories where the Ryzen 5 7640U wins?

A: Yes, the Ryzen 5 7640U wins 3 of the 17 head-to-head benchmark comparisons. These wins are in Cinebench R23 multi-core and single-core tests, plus Geekbench single-core, while the Ryzen 7 7840U wins the remaining 14.

Q: How do the processors compare in Passmark integer and floating-point math?

A: The Ryzen 7 7840U is significantly stronger in both. It scores 90852 in integer math (22.4% higher) and 51767 in floating-point math (20.6% higher) versus the Ryzen 5 7640U's 70483 and 41093.

Where Each One Wins

The benchmark data presents a fascinating split between the two processors. The Ryzen 5 7640U dominates in Cinebench R23 results, which are often associated with long-form rendering workloads. Its multi-core score of 17936 represents a 41% advantage over the Ryzen 7 7840U, and its single-core score of 2532 is 50.9% higher. These are not marginal differences; they suggest the Ryzen 5 is the stronger choice for applications that rely heavily on sustained single-threaded performance or where the workload scales well with high clock speeds on fewer cores.

The Ryzen 7 7840U, by contrast, wins nearly everywhere else. In Geekbench multi-core, it scores 8766 against 8595, a modest 2% edge. The advantages become more pronounced in Passmark's suite of tests. Data compression shows a 16.8% lead (288604 vs 240032), data encryption shows 15.5% (17691 vs 14954), and extended instructions show 16.7% (20432 vs 17019). The largest wins for the Ryzen 7 come in integer math (90852 vs 70483, +22.4%) and floating-point math (51767 vs 41093, +20.6%). Even in physics simulations, the Ryzen 7 leads with 1256 points versus 1169, a 6.9% margin.

The pattern is clear: the Ryzen 7 7840U is the multi-threaded workhorse, winning 14 of 17 head-to-head comparisons. However, the magnitude of the Ryzen 5's wins in Cinebench R23 is striking enough to suggest that specific workloads may favor it disproportionately. The Cinebench R23 results for the Ryzen 7 are anomalously low compared to its other multi-threaded scores, which raises questions about thermal or power management behavior in that specific test.

The Verdict

Choosing between these two processors requires careful attention to the workload. The Ryzen 7 7840U is the safer bet for general multi-threaded productivity. Its consistent wins across Geekbench multi-core, all Passmark categories, and even Cinebench R15 multi-core (1990 vs 1807, +9.2%) demonstrate broad strength. Users who work with large datasets, run encryption, or perform scientific computing will benefit from the 22.4% lead in integer math and 20.6% lead in floating-point math.

The Ryzen 5 7640U is the pick for single-threaded responsiveness and specific rendering scenarios. Its 50.9% lead in Cinebench R23 single-core is enormous, and the 41% lead in multi-core suggests that whatever thermal or power constraints affect the Ryzen 7 in that test do not apply to the Ryzen 5. The Ryzen 5 also wins Geekbench single-core by 2.4%, confirming its edge in lightly-threaded tasks.

Neither processor is a universal winner. The data does not support a blanket recommendation. The Ryzen 7 7840U's overall benchmark average is only 0.2% behind the Ryzen 5, which is statistically negligible, but the distribution of wins matters more than the average. For users who prioritize the specific Cinebench R23 workload, the Ryzen 5 is the obvious choice. For everything else, the Ryzen 7 appears to offer superior performance.

Specification Differences

The two processors share the same fundamental platform but differ in core configuration and power envelope. The Ryzen 5 7640U has 6 cores and 12 threads, while the Ryzen 7 7840U has 8 cores and 16 threads. This 2-core difference is the primary architectural distinction.

Base and boost clocks also differ significantly. The Ryzen 5 7640U runs at a 3.50 GHz base clock and boosts to 4.90 GHz. The Ryzen 7 7840U has a lower base clock of 3.30 GHz but a higher boost clock of 5.10 GHz. This means the Ryzen 7 can reach higher peak frequencies but starts from a slower baseline.

Thermal design power (TDP) also separates the two. The Ryzen 5 7640U is rated at 15W, while the Ryzen 7 7840U is rated at 28W. This nearly 2x difference in TDP likely explains why the Ryzen 7 can sustain higher multi-threaded performance in most tests, but it also implies different thermal management requirements in mobile chassis.

The integrated graphics differ: the Ryzen 5 7640U features the Radeon 760M, while the Ryzen 7 7840U features the Radeon 780M. Both processors share the same AMD Socket FP8, support DDR5 memory with dual-channel configuration, and offer 89.6 GB/s of memory bandwidth. Both support ECC memory and have 20 PCIe Gen 4 lanes.

Architecture Differences

Both processors are built on the same Zen 4 architecture with the Phoenix codename, fabricated on TSMC's 4nm process node. This means they share the same fundamental design philosophy, with a focus on power efficiency and high frequency. Both have 25,000 million transistors on a 178 mm² die, and both feature the same cache hierarchy.

Cache configuration is identical: 64 KB of L1 cache per core, 1 MB of L2 cache per core, and 16 MB of shared L3 cache. Neither processor features 3D V-Cache. This means the performance differences observed in benchmarks cannot be attributed to cache size variations.

The key architectural difference is the core count. The Ryzen 7 7840U's 8 cores versus the Ryzen 5 7640U's 6 cores should theoretically provide a 33% advantage in multi-threaded workloads, assuming perfect scaling. The observed benchmark results, however, show a more complex picture. While the Ryzen 7 wins most multi-threaded tests, the gains range from 2% (Geekbench) to 22.4% (integer math), suggesting that memory bandwidth or power constraints limit scaling.

The higher TDP of the Ryzen 7 7840U (28W vs 15W) is likely the enabling factor for its multi-threaded wins, as it allows the additional cores to sustain higher clocks under load. The Ryzen 5 7640U, with its lower TDP, appears to be thermally constrained in Cinebench R23 but still achieves impressive single-core results due to its 4.90 GHz boost clock.

Head-to-Head Benchmarks

The benchmark data reveals a consistent pattern with a few notable exceptions. The Ryzen 7 7840U wins 14 of 17 comparisons, but the magnitude of its victories varies widely. The largest win for the Ryzen 7 comes in Passmark integer math, where it scores 90852 against 70483, a 22.4% advantage. Floating-point math shows a similar margin at 20.6% (51767 vs 41093).

Data compression and encryption also favor the Ryzen 7 significantly. The compression score of 288604 is 16.8% higher than the Ryzen 5's 240032, and encryption shows a 15.5% lead (17691 vs 14954). Extended instructions follow at 16.7% (20432 vs 17019), and multi-thread performance is 14.8% higher (24782 vs 21115).

The Ryzen 7's lead narrows in other tests. Passmark single-thread is only 1.2% higher (3565 vs 3524), and physics is 6.9% higher (1256 vs 1169). Random string sorting shows a 13% advantage (33757 vs 29382), and Cinebench R15 multi-core is 9.2% higher (1990 vs 1807). Geekbench multi-core is the closest win for the Ryzen 7 at just 2% (8766 vs 8595).

The Ryzen 5 7640U wins decisively in three tests. Cinebench R23 single-core shows a 50.9% advantage (2532 vs 1677.5), which is the largest margin in any comparison. Cinebench R23 multi-core shows a 41% lead (17936 vs 12719). Geekbench single-core is the narrowest win at 2.4% (2127 vs 2077).

These results suggest that the Ryzen 7 7840U's additional cores and higher TDP deliver consistent multi-threaded advantages, but the Ryzen 5 7640U's lower core count and power envelope allow it to excel in specific rendering benchmarks. The Cinebench R23 anomalies are particularly interesting, as they diverge sharply from the Cinebench R15 results where the Ryzen 7 wins both single and multi-core tests. This inconsistency points to workload-specific optimization or thermal throttling behavior that is not captured by the broader benchmark averages.