AMD Ryzen 5 8640HS vs AMD Ryzen AI 5 340 Comparison

The AMD Ryzen 5 8640HS and the AMD Ryzen AI 5 340 are both 6-core, 12-thread mobile processors aimed at thin-and-light laptops, but the benchmark data reveals two distinct personalities. The Ryzen AI 5 340, based on the newer Zen 5 architecture, establishes a clear lead in modern compute-heavy workloads and single-threaded performance. Conversely, the Ryzen 5 8640HS, built on Zen 4, counters with decisive victories in specific integer-heavy and legacy encryption tasks, making it the better choice for those particular use cases. The data shows a 12-to-5 split in benchmark wins favoring the Ryzen AI 5 340, yet the 8640HS holds its ground in enough areas to make the choice highly workload-dependent.

Where Each One Wins

The Ryzen AI 5 340 is the clear winner for content creation and CPU-bound productivity. In Geekbench multicore, it scores 9165 against the 8640HS's 7461, a substantial 18.6% lead that indicates superior performance in video editing, 3D rendering, and code compilation. This dominance extends to Cinebench R23 multicore, where it scores 12532 versus 11486, an 8.3% advantage, and Cinebench R15 multicore, where it wins 1915 to 1845. For users who regularly hammer all cores, the Zen 5 part is the stronger foundation.

The Ryzen AI 5 340 also claims the single-thread crown in most tests. Its Geekbench single-core score of 2140 beats the 8640HS's 1778 by 16.9%, and its Cinebench R23 single-core score of 1915.5 is 10.7% higher than the 1711 posted by the older chip. This translates to snappier everyday responsiveness and better performance in lightly-threaded applications like web browsing and office suites. The PassMark single-thread score confirms the trend, with the AI 5 340 scoring 3683 versus 3584, a 2.7% edge.

The Ryzen 5 8640HS, however, wins in a few specialized niches. Its PassMark data encryption score of 13551 is 18.1% higher than the AI 5 340's 11470, making it the better choice for disk encryption or VPN workloads. It also excels in PassMark integer math, scoring 68173 against 63078, an 8.1% advantage, and in PassMark random string sorting (27316 vs 24970, a 9.4% lead). The 8640HS also takes PassMark multithread (19889 vs 19506, a 2% margin), showing that architectural efficiency in specific instruction paths matters more than raw generational gains.

Architecture Differences

The fundamental split lies in the core architecture. The Ryzen 5 8640HS uses Zen 4, codenamed Hawk Point, while the Ryzen AI 5 340 uses Zen 5, codenamed Krackan Point. Both are built on TSMC's 4nm process, but the die sizes differ: the 8640HS measures 178 mm², while the AI 5 340 is slightly larger at 195 mm². The transistor count for the 8640HS is listed at 25,000 million; the AI 5 340's count is not provided in the data.

Cache configurations show a notable divergence. The 8640HS has a larger L3 cache at 16 MB shared, while the AI 5 340 has only 8 MB. However, the AI 5 340 compensates with a larger L1 cache at 80 KB per core versus 64 KB per core for the 8640HS. Both have 1 MB of L2 per core. This cache architecture likely contributes to the AI 5 340's strong single-thread and Geekbench results, despite the smaller L3 pool.

Memory support also differs. The 8640HS supports DDR5 only, while the AI 5 340 supports both DDR5 and LPDDR5X, offering more flexibility for system designers. Both use a dual-channel memory bus with the same 89.6 GB/s bandwidth. PCIe lanes are another differentiator: the 8640HS offers 20 CPU lanes of Gen 4, while the AI 5 340 provides 16 Gen 4 lanes. The integrated graphics differ as well, with the 8640HS featuring a Radeon 760M and the AI 5 340 a Radeon 840M.

Clock speeds are a major factor in the performance gap. The 8640HS has a base clock of 3.50 GHz and a boost clock of 4.90 GHz. The AI 5 340 has a much lower base clock of 2.00 GHz but a boost clock of 4.80 GHz. The lower base clock likely helps manage power, but the high boost clock allows the Zen 5 cores to reach near-parity in peak single-thread scenarios, while the architectural IPC advantage of Zen 5 does the rest.

Head-to-Head Benchmarks

The largest single victory for the Ryzen AI 5 340 comes in Geekbench multicore, where it scores 9165 versus 7461, a delta of -18.6% from the 8640HS's perspective. This is a massive gap that highlights the efficiency of the Zen 5 architecture in scaling across six cores. The Geekbench single-core test also goes to the AI 5 340 with a score of 2140 versus 1778, a 16.9% delta, reinforcing its per-thread superiority.

Cinebench R23 multicore shows an 8.3% lead for the AI 5 340 (12532 vs 11486), while Cinebench R23 single-core shows a 10.7% lead (1915.5 vs 1711). In Cinebench R15, the pattern is less uniform: the AI 5 340 wins multicore (1915 vs 1845, a 3.7% margin), but the 8640HS wins single-core (268 vs 242.6, a 10.5% margin). This suggests that the older chip's higher boost clock of 4.90 GHz can still prevail in older, less optimized single-thread tests.

The 8640HS's biggest win is in PassMark data encryption, where it scores 13551 against 11470, an 18.1% delta. This is the largest victory for either chip in the entire benchmark suite. It also wins PassMark integer math by 8.1% (68173 vs 63078) and PassMark random string sorting by 9.4% (27316 vs 24970). The PassMark multithread test goes to the 8640HS by a slim 2% margin (19889 vs 19506).

Other tests are closer. PassMark floating point math is nearly a tie, with the AI 5 340 winning 39967 to 39725, a 0.6% margin. PassMark extended instructions favor the AI 5 340 (16440 vs 15855, a 3.6% lead), as does PassMark physics (1095 vs 970, an 11.4% lead). PassMark data compression goes to the AI 5 340 (229796 vs 226544, a 1.4% margin), and PassMark find prime numbers is a near draw (72 vs 70, a 2.8% lead for the AI 5 340).

Specification Differences

The two processors differ in several key specification fields. The 8640HS belongs to the 8000 series, while the AI 5 340 has no series designation in the data. The 8640HS is from the Ryzen 5 generation, while the AI 5 340 is from the Ryzen AI 300 generation, explicitly labeled as Zen 5 / Zen 5c. The 8640HS has a base clock of 3.50 GHz, while the AI 5 340's base clock is 2.00 GHz. Boost clocks are 4.90 GHz and 4.80 GHz, respectively.

L3 cache differs significantly: 16 MB for the 8640HS versus 8 MB for the AI 5 340. L1 cache is 64 KB per core for the 8640HS and 80 KB per core for the AI 5 340. The 8640HS supports only DDR5 memory, while the AI 5 340 supports both DDR5 and LPDDR5X. PCIe lane counts differ: 20 lanes for the 8640HS versus 16 lanes for the AI 5 340. The integrated graphics units are different models: Radeon 760M for the 8640HS and Radeon 840M for the AI 5 340. The die size also differs, with the AI 5 340 at 195 mm² and the 8640HS at 178 mm².

FAQ

Q: Which processor is faster in multi-core workloads?

A: The AMD Ryzen AI 5 340 is consistently faster in multi-core tests. It leads in Geekbench multicore (9165 vs 7461), Cinebench R23 multicore (12532 vs 11486), and Cinebench R15 multicore (1915 vs 1845).

Q: Does the older Ryzen 5 8640HS win any benchmarks?

A: Yes, the 8640HS wins 5 of the 17 head-to-head tests. Its most significant victories are in PassMark data encryption (13551 vs 11470, an 18.1% lead), PassMark integer math (68173 vs 63078, an 8.1% lead), and PassMark random string sorting (27316 vs 24970, a 9.4% lead). It also wins PassMark multithread and Cinebench R15 single-core.

Q: How do the cache configurations compare?

A: The 8640HS has a larger L3 cache at 16 MB shared, while the AI 5 340 has 8 MB. However, the AI 5 340 has a larger L1 cache at 80 KB per core versus 64 KB per core. Both have 1 MB of L2 per core.

Q: What are the memory support differences?

A: The 8640HS supports DDR5 only, while the AI 5 340 supports both DDR5 and LPDDR5X. Both use a dual-channel memory bus with a bandwidth of 89.6 GB/s.

Q: Which chip has better single-thread performance?

A: The AI 5 340 wins most single-thread tests, including Geekbench single-core (2140 vs 1778, a 16.9% lead) and Cinebench R23 single-core (1915.5 vs 1711, a 10.7% lead). However, the 8640HS wins Cinebench R15 single-core (268 vs 242.6, a 10.5% lead).

Q: Do both processors have the same power envelope?

A: Yes, both the Ryzen 5 8640HS and the Ryzen AI 5 340 have a TDP of 28 watts and are designed for the AMD Socket FP8. Both are also unlocked for overclocking? No, both have multiplierUnlocked set to false.