AMD Ryzen 5 PRO 8640U vs AMD Ryzen 7 7840HS Comparison

The AMD Ryzen 5 PRO 8640U and AMD Ryzen 7 7840HS are both 4nm Zen 4 mobile parts, but they target different priorities. The 8640U is a 6-core/12-thread Hawk Point chip with a 28W TDP, while the 7840HS is an 8-core/16-thread Phoenix chip with a 35W TDP. The benchmark data reveals a stark split: the Ryzen 7 wins the majority of tests, but the Ryzen 5 PRO scores some surprising victories in Cinebench, making the choice less obvious than core counts suggest.

Head-to-Head Benchmarks

The most striking result is in Cinebench R23 multicore, where the Ryzen 5 PRO 8640U scores 19982 against the Ryzen 7 7840HS's 15102. That is a 32.3% lead for the 6-core part, a counterintuitive outcome given the 8-core rival's higher thread count. The single-core story is even more lopsided: the 8640U posts 2821 in Cinebench R23 single-core, a 60.2% margin over the 7840HS's 1761. These are not minor wins; they suggest the 8640U runs at significantly higher sustained clocks in this workload, likely due to power management or silicon quality differences.

The Ryzen 7 7840HS takes its revenge across the Passmark suite. In integer math, it scores 98682 versus 74875 for the 8640U, a 24.1% advantage. Floating point math shows a similar gap: 59921 vs 45265, or 24.5% in favor of the 7840HS. Data compression is a clear 7840HS win at 345536 vs 260925 (24.5% ahead), and data encryption follows at 20627 vs 15843 (23.2% ahead). The 7840HS also wins extended instructions (25747 vs 19130, +25.7%) and find prime numbers (88 vs 78, +11.4%).

In Passmark multithread, the 7840HS scores 28633 against 22795, a 20.4% lead, and physics shows 1376 vs 1154 (16.1% ahead). Random string sorting goes to the 7840HS at 40364 vs 32114 (20.4%). The single-thread Passmark tests are essentially a tie: 3753 vs 3732, a mere 0.6% edge for the 7840HS. In Cinebench R15, the 7840HS wins multicore (2222.84 vs 2014, +9.4%), but the 8640U wins singlecore (284 vs 274, +3.6%). The win tally is decisive: 12 for the Ryzen 7, 3 for the Ryzen 5 PRO.

FAQ

Q: Why does the Ryzen 5 PRO 8640U win Cinebench R23 multicore by 32.3% despite having fewer cores?

A: The data shows the 8640U scoring 19982 vs 15102. This likely reflects sustained boost behavior under the R23 workload, where the 6-core part maintains higher clocks than the 8-core 7840HS, which may be power-limited at its 35W TDP in that specific test.

Q: Which chip is better for heavily threaded productivity like video encoding?

A: The Ryzen 7 7840HS is the clear choice. It leads by 20.4% in Passmark multithread (28633 vs 22795), and wins all the math-heavy Passmark tests (integer, floating point, data compression) by margins between 23.2% and 25.7%.

Q: Is there any scenario where the 8640U's single-core advantage matters?

A: Yes. The 8640U leads Cinebench R23 single-core by 60.2% and R15 single-core by 3.6%. For lightly-threaded tasks that rely on single-core speed, the 8640U is faster, though the Passmark single-thread scores are nearly identical (0.6% apart).

Q: How do these chips compare to other CPUs in their price range?

A: The 8640U sits at the 81st percentile vs all CPUs, with an average benchmark score of 30254. Its nearest rival is the AMD Ryzen 7 2700X (30213, +0.1%). The 7840HS also sits at the 81st percentile, averaging 29955, and is exactly matched by the AMD Ryzen 7 8845HS (0% delta).

Q: Do both chips have the same memory bandwidth?

A: Yes. Both support DDR5 dual-channel memory with a bandwidth of 89.6 GB/s. They also share the same cache structure: 64 KB L1 per core, 1 MB L2 per core, and 16 MB shared L3.

Q: Which chip has better integrated graphics?

A: The Ryzen 7 7840HS features the Radeon 780M, while the Ryzen 5 PRO 8640U has the Radeon 760M. The 7840HS's iGPU is a tier higher, which typically indicates more compute units, though no direct iGPU benchmarks are provided here.

Architecture Differences

Both processors are built on TSMC's 4nm process node and share the same Zen 4 architecture, but they come from different families. The 8640U uses the Hawk Point codename, part of the 8000 series, while the 7840HS uses the Phoenix codename from the 7000 series. Despite this, they have identical transistor counts (25,000 million) and die sizes (178 mm²), confirming they are closely related silicon.

The core configurations differ: the 8640U has 6 cores/12 threads, while the 7840HS has 8 cores/16 threads. This is the primary architectural distinction. Cache is identical across both chips: 64 KB L1 per core, 1 MB L2 per core, and 16 MB shared L3. Both support ECC memory and use Gen 4 PCIe with 20 lanes (CPU only). The 8640U ships in an AMD Socket FP7, while the 7840HS uses Socket FP8, though the 7840HS part numbers include FP7r2 and FP7 variants as well.

The integrated GPU is a major differentiator. The 8640U pairs with the Radeon 760M, while the 7840HS has the Radeon 780M. This suggests the 7840HS is positioned for more graphics-intensive work, even without iGPU benchmark numbers. Both are mobile market segments, and both are production active.

Specification Differences

The core count is the headline: 6 vs 8 cores, and 12 vs 16 threads. Clock speeds favor the Ryzen 7: it has a 3.80 GHz base and 5.10 GHz boost, compared to the 8640U's 3.50 GHz base and 4.90 GHz boost. The TDP also differs, with the 7840HS rated at 35W versus 28W for the 8640U.

The socket is different: FP7 for the 8640U, FP8 for the 7840HS. Integrated graphics are different, as noted: Radeon 760M vs Radeon 780M. The release date is listed for the 8640U as 2024-04-15, while the 7840HS has no release date in the data. Neither chip has a launch MSRP. Both are unlocked multipliers set to false, so no overclocking via multiplier. The part numbers differ: the 8640U is 100-000001318(FP7r2),100-000001378(FP7), while the 7840HS is 100-000000955(FP7r2)100-000000964(FP7)100-000001129(FP8).

The Verdict

The data paints a clear picture for most workloads: the Ryzen 7 7840HS is the better all-around processor. It wins 12 out of 15 head-to-head benchmarks, with decisive margins in Passmark multithread (20.4%), integer math (24.1%), and data compression (24.5%). Its 8-core/16-thread configuration and higher TDP deliver tangible performance in sustained multi-threaded tasks. The 3.80 GHz base and 5.10 GHz boost clocks are also higher than the 8640U's 3.50 GHz and 4.90 GHz.

However, the Ryzen 5 PRO 8640U is not a pushover. Its Cinebench R23 results are extraordinary: a 32.3% multicore win and a 60.2% single-core win over the 7840HS. These are massive margins that cannot be ignored. If your workload is dominated by Cinebench-style rendering, the 8640U is objectively faster. That said, the 7840HS counters with a 9.4% win in Cinebench R15 multicore, indicating the 8640U's R23 advantage may be workload-specific rather than universal.

For a neutral recommendation based strictly on scores: the 7840HS is the safer pick for general productivity, given its broad wins across the Passmark suite. The 8640U is a specialist that excels in specific rendering tasks but lags in most other metrics. The average benchmark scores are close (30254 vs 29955), but the distribution of wins favors the 7840HS.

Where Each One Wins

The Ryzen 7 7840HS wins in: All Passmark compute workloads, including integer math, floating point math, data compression, data encryption, extended instructions, prime number finding, physics, random string sorting, and multithread tests. It also wins Cinebench R15 multicore. This makes it the choice for video encoding, 3D rendering, scientific computation, encryption, and any workload that scales with core count. Its higher TDP (35W vs 28W) supports sustained performance in these tasks.

The Ryzen 5 PRO 8640U wins in: Cinebench R23 multicore and single-core, plus Cinebench R15 single-core. The R23 numbers are exceptional (19982 and 2821), suggesting the 6-core part can hit very high boost clocks when thermals and power allow. This makes it the pick for users who run Cinebench R23 as their primary benchmark or who have workloads that mirror its behavior—likely short, bursty rendering tasks that benefit from a single powerful core or a small number of high-clocked cores. The Passmark single-thread scores are nearly identical (0.6% apart), so the 8640U's single-core advantage is not universal.

If you need a do-everything chip for mixed productivity, the 7840HS's 12 wins and higher multithread scores (28633 vs 22795) make it the default recommendation. If you specifically run Cinebench R23 and want the best possible score, the 8640U is the unexpected but clear winner. Choose based on your dominant workload, not the core count.