AMD Ryzen 5 PRO 8640U vs AMD Ryzen 5 PRO 8645HS Comparison

Head-to-Head Benchmarks

The database shows a near-even split between these two mobile processors, with the AMD Ryzen 5 PRO 8645HS taking 9 benchmark wins and the AMD Ryzen 5 PRO 8640U taking 8. The overall average benchmark scores place the 8645HS at 30,879 against the 8640U's 30,254, a margin of roughly 2% in favor of the higher-TDP part. In Cinebench testing, the 8640U actually comes out ahead across the board, though by very narrow margins. The 8640U leads the R15 multicore test with 2,014 points versus 1,989, a 1.2% advantage, and matches that same 1.2% edge in R20 multicore with 8,392 against 8,291. The R23 multicore result shows 19,982 for the 8640U versus 19,742 for the 8645HS, again a 1.2% gap. Single-core results follow the same pattern: the 8640U wins R15 single-core with 284 against 280 (1.4% ahead), R20 single-core with 1,184 versus 1,170, and R23 single-core with 2,821 versus 2,787. These are small but consistent advantages for the lower-power chip in rendering workloads.

The 8645HS fights back in Passmark tests with more pronounced wins. Data encryption shows the biggest gap: 17,387 for the 8645HS versus 15,843 for the 8640U, a 9.7% advantage. Extended instructions follow closely with 21,212 against 19,130, a 10.9% lead. Random string sorting shows 35,472 versus 32,114, a 10.5% margin. Multithread performance favors the 8645HS at 23,569 against 22,795, a 3.4% edge, and single-thread performance also goes to the 8645HS with 3,858 versus 3,732, another 3.4% margin. Physics testing gives the 8645HS 1,208 points versus 1,154, a 4.7% win. Data compression goes to the 8645HS with 265,826 against 260,925, a 1.9% edge, and floating-point math shows a narrow 0.5% win at 45,481 versus 45,265.

The 8640U takes a few remaining Passmark tests. Integer math goes its way with 74,875 versus 72,740, a 2.9% advantage. Find prime numbers shows 78 versus 73, a 6.4% edge for the 8640U. These wins help explain why the 8640U keeps the overall score close despite losing several larger-margin tests.

Where Each One Wins

The 8645HS is the stronger choice for workloads that stress encryption, sorting, and instruction-heavy processing. The 9.7% lead in data encryption and 10.9% lead in extended instructions suggest it handles cryptographic tasks and SIMD-style workloads with noticeably more headroom. The 10.5% advantage in random string sorting points to better memory access patterns or higher sustained clocks under irregular workloads. Multithread and single-thread Passmark scores both favor the 8645HS by 3.4%, indicating a general throughput advantage in mixed computing tasks. Physics simulation also favors the 8645HS by 4.7%, which may matter for lightweight simulation or gaming physics.

The 8640U wins in Cinebench rendering across all versions tested, despite its lower base clock of 3.50 GHz versus 4.30 GHz and lower boost clock of 4.90 GHz versus 5.00 GHz. The consistent 1.2% to 1.4% margins in R15, R20, and R23 suggest the 28 W TDP part sustains performance efficiently in rendering workloads, possibly due to better thermal behavior in the database's test conditions. The 8640U also wins integer math by 2.9% and prime number finding by 6.4%, indicating a slight edge in purely arithmetic or integer-heavy tasks. For productivity suites that mix integer operations with occasional single-core bursts, the 8640U holds its own.

The overall pattern is that the 8645HS dominates in specialized instruction sets and encryption, while the 8640U leads in conventional rendering benchmarks. Neither chip has a sweeping advantage; the largest single delta is the 10.9% extended instructions win for the 8645HS, and the largest for the 8640U is the 6.4% prime numbers result.

The Verdict

The data supports a clear split based on workload profile. If the primary use involves encryption, data compression, sorting large datasets, or running applications that leverage extended instruction sets, the AMD Ryzen 5 PRO 8645HS is the better pick. Its 9.7% and 10.9% wins in encryption and extended instructions are the largest margins in this comparison, and the multithread and single-thread Passmark advantages reinforce its position for general compute. The 45 W TDP part also carries a higher base clock of 4.30 GHz and boost clock of 5.00 GHz, which correlates with its Passmark wins.

If the workload leans toward Cinebench-style rendering or integer-heavy arithmetic, the AMD Ryzen 5 PRO 8640U is the better option. It wins all six Cinebench tests, including the R23 multicore score of 19,982, and its 28 W TDP suggests it can deliver these results in a thinner, cooler chassis. The 8640U's integer math and prime number wins add to its appeal for number-crunching tasks. For users prioritizing portability and battery life, the 28 W TDP is a meaningful advantage, though the database does not include battery or thermal measurements.

Both processors share the same Zen 4 architecture, Hawk Point codename, 6 cores, 12 threads, and 16 MB of shared L3 cache. The choice is not about core count or architecture; it is about whether the higher TDP and clock speeds of the 8645HS translate into the specific benchmarks that matter. For encryption and instruction-heavy work, they do. For rendering, they do not.

FAQ

Q: Which processor has the higher average benchmark score?

A: The AMD Ryzen 5 PRO 8645HS has an average benchmark score of 30,879, while the AMD Ryzen 5 PRO 8640U scores 30,254.

Q: How do the two compare in Cinebench R23 multicore?

A: The 8640U leads with 19,982 points versus 19,742 for the 8645HS, a 1.2% advantage for the 8640U.

Q: Is there a big difference in encryption performance?

A: Yes, the 8645HS scores 17,387 in Passmark data encryption versus 15,843 for the 8640U, a 9.7% lead.

Q: Which processor has the higher TDP?

A: The 8645HS has a TDP of 45 W, while the 8640U has a TDP of 28 W.

Q: Do both processors have the same number of cores and threads?

A: Yes, both have 6 cores and 12 threads.

Q: What is the clock speed difference between the two?

A: The 8645HS has a base clock of 4.30 GHz and boost clock of 5.00 GHz. The 8640U has a base clock of 3.50 GHz and boost clock of 4.90 GHz.

Architecture Differences

Both processors are built on the same fundamental architecture. They share the Zen 4 microarchitecture, the Hawk Point codename, and the 8000 series family designation. Both are manufactured on a 4 nm process at TSMC, with 25,000 million transistors and a die size of 178 mm². There is no difference in cache configuration: both have 64 KB of L1 cache per core, 1 MB of L2 cache per core, and 16 MB of shared L3 cache. Neither has any 3D V-Cache. Both support DDR5 memory in a dual-channel configuration with 89.6 GB/s of memory bandwidth, and both support ECC memory. The PCIe interface is identical: Gen 4 with 20 lanes from the CPU. Both integrate the Radeon 760M graphics solution.

The architecture differences are therefore minimal. The only meaningful architectural separation comes from the TDP classification and the clock speeds that accompany it. The 8645HS is a 45 W part with a 4.30 GHz base and 5.00 GHz boost, while the 8640U is a 28 W part with a 3.50 GHz base and 4.90 GHz boost. Both use the same AMD Socket FP7, and both have the same production status of Active. The market segment for both is Mobile. Both were released on the same date, 2024-04-15. Neither has an unlocked multiplier. The part numbers differ slightly, with the 8645HS listed as 100-000001315(FP7r2) and 100-000001388(FP7), while the 8640U is 100-000001318(FP7r2) and 100-000001378(FP7).

Specification Differences

The specification table shows only a handful of differences between the two processors. The base clock differs: the 8645HS runs at 4.30 GHz, while the 8640U runs at 3.50 GHz. The boost clock also differs: 5.00 GHz for the 8645HS versus 4.90 GHz for the 8640U. The TDP is the largest specification gap, with the 8645HS rated at 45 W and the 8640U at 28 W. The part numbers differ as listed above. All other specifications are identical: 6 cores, 12 threads, same cache hierarchy, same memory support, same integrated graphics, same socket, same process node, same foundry, same transistor count, same die size, same PCIe configuration, and same release date. Neither processor has a launch MSRP recorded in the database, and neither has an unlocked multiplier. The percentile rankings differ slightly, with the 8645HS at the 82nd percentile among all CPUs and the 8640U at the 81st percentile.