AMD Ryzen 5 8640HS vs AMD Ryzen 9 6900HX Comparison

The AMD Ryzen 9 6900HX and AMD Ryzen 5 8640HS are two mobile processors that, despite their different positioning, end up in a fascinating statistical dead heat. The data shows the 6900HX wins 12 of the 17 head-to-head benchmark comparisons, while the 8640HS takes 5. However, their average benchmark scores are nearly identical, with the 6900HX at 26,274 and the 8640HS at 26,106, placing both in the 78th percentile against all CPUs. This suggests a split personality: one chip is a brute-force multi-threaded specialist, while the other is a more efficient single-threaded performer. The question is not which is faster overall, but which type of workload you prioritize.

Head-to-Head Benchmarks

The Ryzen 9 6900HX dominates in nearly every multi-threaded and throughput-oriented test. The largest margin comes in PassMark data encryption, where the 6900HX scores 19,118 against the 8640HS's 13,551, a massive 41.1% advantage. This is followed by PassMark data compression, where the 6900HX's 306,184 score beats the 8640HS's 226,544 by 35.2%. In Geekbench multicore, the gap is 32%, with scores of 9,850 and 7,461 respectively. The pattern continues with PassMark extended instructions (20,849 vs 15,855, a 31.5% lead), PassMark integer math (89,388 vs 68,173, a 31.1% lead), and PassMark floating point math (49,981 vs 39,725, a 25.8% lead). Even in Cinebench R23 multicore, the 6900HX's 13,497 score tops the 8640HS's 11,486 by 17.5%. These are not marginal victories; they represent a substantial generational gap in raw parallel processing capability.

The Ryzen 5 8640HS, however, claims the single-threaded crown. In Cinebench R23 single-core, it scores 1,711 versus the 6900HX's 1,558, an 8.9% advantage. It also wins Cinebench R15 single-core (268 vs 249, a 7.1% lead) and PassMark single-thread (3,584 vs 3,409, a 4.9% lead). The 8640HS also shows an unexpected strength in PassMark find prime numbers, scoring 70 compared to the 6900HX's 63, a 10% win. Interestingly, the 6900HX wins Geekbench single-core (1,881 vs 1,778, a 5.8% lead), showing that the single-thread story is not uniform across all benchmarks. This mixed picture suggests the 8640HS's newer architecture gives it an edge in some legacy and integer-heavy single-thread tasks, while the 6900HX's higher clock speed compensates in others.

Looking at the broader picture, the 6900HX's wins are consistently large, often exceeding 20%, while the 8640HS's wins are smaller, mostly in the 5-10% range. The 6900HX's biggest losses are the 8640HS's biggest wins, but the magnitude of the 6900HX's victories far outweighs the 8640HS's. For instance, the 8640HS's 8.9% Cinebench R23 single-core win is dwarfed by the 6900HX's 17.5% multicore win in the same suite. The data implies that for any workload that can utilize multiple cores, the 6900HX is decisively superior.

FAQ

Q: Which processor has the higher average benchmark score?

A: The AMD Ryzen 9 6900HX has an average benchmark score of 26,274, which is slightly higher than the AMD Ryzen 5 8640HS's 26,106. The difference is minimal, and both processors sit in the 78th percentile of all CPUs.

Q: How much faster is the Ryzen 9 6900HX in Cinebench R23 multicore?

A: The Ryzen 9 6900HX scores 13,497 in Cinebench R23 multicore, which is 17.5% higher than the Ryzen 5 8640HS's score of 11,486.

Q: Is the Ryzen 5 8640HS better in any benchmark?

A: Yes, the Ryzen 5 8640HS wins in Cinebench R23 single-core (1,711 vs 1,558), Cinebench R15 single-core (268 vs 249), PassMark single-thread (3,584 vs 3,409), and PassMark find prime numbers (70 vs 63). It also wins PassMark singlethread, which is the same test as PassMark single-thread.

Q: What is the difference in TDP between the two processors?

A: The Ryzen 9 6900HX has a TDP of 45 watts, while the Ryzen 5 8640HS has a TDP of 28 watts. This suggests the 8640HS is designed for more power-efficient operation.

Q: Do both processors support the same memory type?

A: Yes, both the AMD Ryzen 9 6900HX and the AMD Ryzen 5 8640HS support DDR5 memory with a dual-channel memory bus. However, the 8640HS has a higher memory bandwidth of 89.6 GB/s compared to the 6900HX's 76.8 GB/s.

Q: Which processor has more cores and threads?

A: The AMD Ryzen 9 6900HX has 8 cores and 16 threads, while the AMD Ryzen 5 8640HS has 6 cores and 12 threads.

Where Each One Wins

The Ryzen 9 6900HX is the clear choice for compute-heavy, multi-threaded workloads. Its 41.1% lead in data encryption and 35.2% lead in data compression make it ideal for tasks like file archiving, disk encryption, or any database operation that relies on these functions. The 32% advantage in Geekbench multicore and 31.1% lead in integer math point to strength in video rendering, 3D modeling, and software compilation, where all available cores are saturated. The 25.8% lead in floating-point math also makes it suitable for scientific simulations and financial modeling that require heavy numerical computation. For users who run virtual machines, render videos, or work with large datasets, the 6900HX's 12 wins provide a decisive performance edge.

The Ryzen 5 8640HS, despite its fewer cores, wins in scenarios where single-thread latency is king. Its 8.9% lead in Cinebench R23 single-core and 7.1% lead in Cinebench R15 single-core suggest it handles everyday tasks like web browsing, office productivity, and light photo editing with slightly more responsiveness. The 10% win in PassMark find prime numbers is a specific but telling metric for certain encryption algorithms and mathematical workloads that are not easily parallelized. The 4.9% win in PassMark single-thread further cements its position as a snappy daily driver. However, these wins are narrower in margin, meaning the 6900HX is not far behind in these tasks, while the 8640HS is significantly behind in multi-threaded tasks.

The data suggests a use-case split based on core count versus architectural efficiency. The 6900HX leverages its 8 cores and 16 threads to plow through parallel workloads, while the 8640HS uses its newer Zen 4 architecture to deliver better performance on a per-thread basis. The 8640HS also has a 10% win in find prime numbers, which is a unique strength. If your application is single-threaded, the 8640HS offers a modest but consistent advantage. If your application can use multiple cores, the 6900HX offers a massive advantage.

Specification Differences

The two processors differ fundamentally in their core configurations. The Ryzen 9 6900HX offers 8 cores and 16 threads, while the Ryzen 5 8640HS offers 6 cores and 12 threads. The base clock speeds differ, with the 6900HX at 3.30 GHz and the 8640HS at 3.50 GHz. Both share the same boost clock of 4.90 GHz. The TDP is a major differentiator: the 6900HX has a 45-watt TDP, while the 8640HS has a 28-watt TDP. The socket also differs, with the 6900HX using AMD Socket FP7 and the 8640HS using AMD Socket FP8. The cache hierarchy is different, as the 8640HS has double the L2 cache per core (1 MB vs 512 KB), while both share the same 16 MB of shared L3 cache. The 6900HX has an unlocked multiplier, while the 8640HS is locked. The integrated graphics differ, with the 6900HX featuring a Radeon 680M and the 8640HS featuring a Radeon 760M. Finally, the memory bandwidth is higher on the 8640HS at 89.6 GB/s versus the 6900HX's 76.8 GB/s, despite both supporting dual-channel DDR5.

Architecture Differences

The architectural divide is significant. The Ryzen 9 6900HX is built on the Zen 3+ architecture, codenamed Rembrandt, and belongs to the 6000 series. It uses a 6 nm process node from TSMC and has a die size of 208 mm². The Ryzen 5 8640HS, on the other hand, is built on the newer Zen 4 architecture, codenamed Hawk Point, and belongs to the 8000 series. It uses a more advanced 4 nm process node from TSMC and has a die size of 178 mm². The 8640HS also features a transistor count of 25,000 million, while the 6900HX's transistor count is not specified in the data. The L2 cache is a notable difference: the 8640HS has 1 MB per core, while the 6900HX has 512 KB per core. This architectural shift to a smaller node and newer core design explains the 8640HS's single-thread performance advantage despite having fewer cores. The 8640HS's release date is also listed as 2023-12-05, indicating it is a more recent design.

The Verdict

The data presents a clear, if nuanced, verdict. The AMD Ryzen 9 6900HX is the superior processor for any workload that can leverage multiple cores. Its 12 benchmark wins, including decisive margins in encryption (41.1%), compression (35.2%), and Geekbench multicore (32%), make it the unambiguous choice for content creators, developers, and power users who run demanding applications. The 6900HX's 8 cores and 16 threads, combined with its 45-watt TDP, deliver the raw throughput needed for heavy lifting.

The AMD Ryzen 5 8640HS is the better choice for users who prioritize single-thread responsiveness and power efficiency. Its 5 wins in single-thread and prime number tests, coupled with its 28-watt TDP, make it an attractive option for thin-and-light laptops where battery life and everyday snappiness matter more than multi-core muscle. The 8640HS's newer Zen 4 architecture and 4 nm process node provide a modern foundation, and its higher memory bandwidth of 89.6 GB/s is a tangible benefit.

However, the overall average scores are nearly identical, with the 6900HX at 26,274 and the 8640HS at 26,106. This means that for mixed or general use, the difference may be negligible. The decision ultimately rests on the nature of your primary applications. If you need to render, compile, or encode, the 6900HX's multi-threaded dominance is undeniable. If you need a responsive, efficient processor for standard tasks, the 8640HS's single-thread edge and lower power draw make it a compelling alternative. The 6900HX is also unlocked, offering overclocking potential that the 8640HS lacks. In short, the 6900HX is a performance-first processor, while the 8640HS is an efficiency-first processor with a modern architecture.