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

The Verdict

The AMD Ryzen 5 PRO 8640HS and AMD Ryzen AI 5 PRO 340 are both 6-core, 12-thread mobile processors with a 28 W TDP, but they are built for different jobs. The data shows the 8640HS is the clear multi-threaded workhorse, winning 10 of the 15 head-to-head benchmark comparisons. Its Cinebench R23 multi-core score of 18104 crushes the AI 5 PRO 340's 11534, a 57% gap that defines this matchup. If your workload is rendering, compiling, or heavy batch processing, the 8640HS is the pick.

The Ryzen AI 5 PRO 340 fights back in single-threaded and physics-based tasks. It wins PassMark single-thread with 3758 versus 3561, a 5.2% edge, and tops the 8640HS in Cinebench R15 single-core (276 vs 257, a 6.9% lead). It also wins PassMark physics (1084 vs 1043, a 3.8% edge) and prime number finding (74 vs 71, a 4.1% lead). For responsiveness in lightly threaded apps or older software, the newer Zen 5 part holds its own.

Both chips sit at the 80th percentile among all CPUs in the database. The 8640HS averages 28478 benchmark points, while the AI 5 PRO 340 averages 27932. That is a narrow overall margin of about 2%, but the distribution matters more than the average. The 8640HS is the safer choice for sustained multi-core work, while the AI 5 PRO 340 offers a snappier feel in single-threaded scenarios and adds LPDDR5X memory support.

Architecture Differences

The 8640HS uses Zen 4 architecture on the Hawk Point codename, part of the 8000 series. The AI 5 PRO 340 uses Zen 5 architecture on the Krackan Point codename, part of the Ryzen AI PRO 300 series. Both are built on TSMC's 4 nm process, but the die sizes differ: the 8640HS measures 178 mm², while the AI 5 PRO 340 is larger at 195 mm². The 8640HS has 25,000 million transistors; no transistor count is recorded for the AI 5 PRO 340.

Cache layouts diverge significantly. The 8640HS provides 64 KB of L1 per core, 1 MB of L2 per core, and 16 MB of shared L3. The AI 5 PRO 340 offers 80 KB of L1 per core and 1 MB of L2 per core, but only 8 MB of L3. That halved L3 pool helps explain why the 8640HS pulls so far ahead in multi-threaded tests despite the older architecture.

Clock speeds also differ. The 8640HS has a 3.50 GHz base clock and a 4.90 GHz boost. The AI 5 PRO 340 starts lower at 2.00 GHz base but boosts to 4.80 GHz. The AI 5 PRO 340 also uses a hybrid core arrangement, listed as Zen 5 / Zen 5c, which is not present in the 8640HS's uniform Zen 4 setup.

The integrated graphics differ as well. The 8640HS carries the Radeon 760M, while the AI 5 PRO 340 has the Radeon 840M. Memory support is a key differentiator: the AI 5 PRO 340 accepts DDR5 and LPDDR5X, while the 8640HS is limited to DDR5 only. Both run dual-channel memory at 89.6 GB/s and support ECC memory. PCIe connectivity differs, with the 8640HS offering Gen 4 with 20 CPU lanes versus the AI 5 PRO 340's Gen 4 with 16 CPU lanes.

The sockets are not interchangeable. The 8640HS uses AMD Socket FP7, while the AI 5 PRO 340 uses AMD Socket FP8. Both chips have locked multipliers, so overclocking is not on the table for either.

Head-to-Head Benchmarks

The biggest single win for the 8640HS is Cinebench R23 multi-core, where it scores 18104 against 11534, a 57% lead. That is the largest delta in the entire comparison and reflects the combination of higher base clock, larger L3 cache, and uniform Zen 4 cores. The same pattern appears in Cinebench R15 multi-core, where the 8640HS wins 1824 to 1743, a more modest 4.6% edge.

The 8640HS also dominates in PassMark workloads. Data encryption shows a 33.4% lead (14962 vs 11212), random string sorting a 24.3% lead (30235 vs 24334), and extended instructions a 17.7% lead (18507 vs 15721). Multithread scoring favors the 8640HS by 11.7% (21465 vs 19215), integer math by 10.4% (69839 vs 63233), floating point math by 8.5% (43019 vs 39662), and data compression by 11.2% (246446 vs 221581).

The AI 5 PRO 340 wins the single-threaded battles. PassMark single-thread shows 3758 vs 3561, a 5.2% lead. Cinebench R15 single-core goes to the AI 5 PRO 340 at 276 vs 257, a 6.9% edge. PassMark physics favors the AI 5 PRO 340 at 1084 vs 1043, a 3.8% lead, and prime number finding goes its way at 74 vs 71, a 4.1% margin. Interestingly, Cinebench R23 single-core does not follow the same pattern: the 8640HS wins 2555 to 1802, a 41.8% lead that contradicts the R15 single-core result.

The AI 5 PRO 340 also lacks a Cinebench R20 score in the database, so no multi-core or single-core R20 comparison is possible. The recorded data covers 15 head-to-head tests total, with the 8640HS taking 10 and the AI 5 PRO 340 taking 5.

Specification Differences

Both chips share 6 cores, 12 threads, 28 W TDP, TSMC 4 nm process, dual-channel memory, 89.6 GB/s bandwidth, ECC support, and Gen 4 PCIe. The differences are as follows:

• Base clock: 3.50 GHz on the 8640HS, 2.00 GHz on the AI 5 PRO 340
• Boost clock: 4.90 GHz on the 8640HS, 4.80 GHz on the AI 5 PRO 340
• Socket: FP7 on the 8640HS, FP8 on the AI 5 PRO 340
• Architecture: Zen 4 on the 8640HS, Zen 5 on the AI 5 PRO 340
• Codename: Hawk Point on the 8640HS, Krackan Point on the AI 5 PRO 340
• Process node: both 4 nm, but die size is 178 mm² for the 8640HS and 195 mm² for the AI 5 PRO 340
• Transistors: 25,000 million for the 8640HS, not recorded for the AI 5 PRO 340
• L1 cache: 64 KB per core on the 8640HS, 80 KB per core on the AI 5 PRO 340
• L2 cache: 1 MB per core on both
• L3 cache: 16 MB shared on the 8640HS, 8 MB on the AI 5 PRO 340
• Memory support: DDR5 on the 8640HS, DDR5 and LPDDR5X on the AI 5 PRO 340
• PCIe lanes: 20 CPU lanes on the 8640HS, 16 CPU lanes on the AI 5 PRO 340
• Integrated graphics: Radeon 760M on the 8640HS, Radeon 840M on the AI 5 PRO 340
• Release date: 2024-04-15 for the 8640HS, 2025-01-05 for the AI 5 PRO 340
• Part number: 100-000001354 (FP7r2) and 100-000001382 (FP7) for the 8640HS, 100-000001600 for the AI 5 PRO 340

FAQ

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

A: The AMD Ryzen 5 PRO 8640HS wins every multi-core benchmark in the comparison. Its Cinebench R23 multi-core score of 18104 is 57% higher than the AI 5 PRO 340's 11534. PassMark multithread also favors the 8640HS, 21465 to 19215, an 11.7% lead.

Q: Does the Ryzen AI 5 PRO 340 win any benchmarks?

A: Yes. It wins Cinebench R15 single-core (276 vs 257, a 6.9% lead), PassMark single-thread (3758 vs 3561, a 5.2% lead), PassMark physics (1084 vs 1043, a 3.8% lead), and PassMark find prime numbers (74 vs 71, a 4.1% lead). It takes 5 of the 15 recorded head-to-head tests.

Q: Why does the 8640HS have such a large L3 cache advantage?

A: The 8640HS has 16 MB of shared L3 cache, while the AI 5 PRO 340 has only 8 MB. The data shows this correlates with the 8640HS's dominance in multi-threaded and data-heavy workloads like encryption, compression, and random string sorting.

Q: Do both CPUs support the same memory types?

A: No. The 8640HS supports DDR5 only. The AI 5 PRO 340 supports both DDR5 and LPDDR5X. Both run dual-channel at 89.6 GB/s and support ECC memory.

Q: Are these CPUs compatible with the same motherboard socket?

A: No. The 8640HS uses AMD Socket FP7, while the AI 5 PRO 340 uses AMD Socket FP8. They are not interchangeable.

Q: Which CPU has better integrated graphics?

A: The 8640HS has the Radeon 760M, while the AI 5 PRO 340 has the Radeon 840M. No benchmark scores are recorded for either iGPU in the database, so a performance comparison cannot be made from this data.

Where Each One Wins

The AMD Ryzen 5 PRO 8640HS is the choice for compute-heavy, sustained workloads. Its 57% lead in Cinebench R23 multi-core and 33.4% lead in data encryption show that the larger L3 cache and higher base clock pay off when the CPU is saturated across all cores. Random string sorting, a 24.3% win, and extended instructions, a 17.7% win, point to strength in data processing and cryptographic work. For rendering, video encoding, batch file conversion, or any task that keeps all 12 threads busy for long stretches, the 8640HS is the better engine.

The AMD Ryzen AI 5 PRO 340 is the pick for single-threaded responsiveness and lighter workloads. Its PassMark single-thread score of 3758 beats the 8640HS by 5.2%, and its Cinebench R15 single-core win of 276 vs 257 suggests snappier interaction in everyday applications. The physics benchmark win (1084 vs 1043) and prime number finding win (74 vs 71) reinforce the pattern. If the workload is mostly office apps, web browsing, or software that rarely uses more than one or two cores, the AI 5 PRO 340 offers a slightly faster feel.

The AI 5 PRO 340 also has the edge in platform flexibility. Its support for LPDDR5X memory gives laptop designers more options for compact, low-power systems, while the 8640HS is locked to DDR5. The larger 195 mm² die on the AI 5 PRO 340 suggests a more complex design, but the architecture differences show up mainly in single-threaded gains, not multi-core throughput.

For buyers choosing between these two in a mobile workstation or high-end business laptop, the decision comes down to workload shape. The 8640HS wins the average benchmark comparison at 28478 points versus 27932, and its multi-core dominance makes it the safer all-rounder for mixed professional use. The AI 5 PRO 340 is the better choice when single-threaded speed, LPDDR5X compatibility, and a newer socket matter more than raw multi-threaded output. Both sit at the 80th percentile of all CPUs in the database, so neither is a weak option, but the data clearly favors the 8640HS for heavy lifting.