AMD Ryzen 5 8645HS vs AMD Ryzen 7 8840HS Comparison

Both the AMD Ryzen 7 8840HS and the AMD Ryzen 5 8645HS are part of the 8000 series, built on the Zen 4 architecture with the Hawk Point codename. They share the same 4 nm TSMC process node, the same 25,000 million transistor count, and the same 178 mm² die size, making them close relatives. However, the benchmark data reveals a clear performance split: the Ryzen 7 8840HS wins 11 of the 15 head-to-head comparisons, while the Ryzen 5 8645HS takes the remaining 4. This makes the choice between them less about raw architecture and more about how their specific configurations align with your workload priorities.

Head-to-Head Benchmarks

The most significant victory for the Ryzen 7 8840HS comes in the PassMark integer math test, where it scores 90,382 against the Ryzen 5's 72,640—a commanding 24.4% advantage. This is the largest single delta in the entire comparison and reflects the extra two cores and four threads working in parallel. Floating-point math follows a similar pattern, with the Ryzen 7 leading 52,582 to 44,833, a 17.3% gap. These two results alone show that the 8840HS is substantially better at raw computational throughput in integer and floating-point workloads.

The 8840HS also demonstrates strong performance in data-related tasks. In PassMark data compression, it scores 292,888 versus 265,483, a 10.3% lead. Data encryption shows an even bigger margin: 17,650 against 15,588, which is 13.2% ahead. Random string sorting also favors the 8840HS, with scores of 35,517 versus 31,748, an 11.9% difference. These wins suggest the 8840HS handles memory-intensive and data-transformation tasks more efficiently.

Multithreaded performance is another area where the 8840HS pulls ahead. In PassMark multithread, it scores 24,990 versus 22,586, a 10.6% advantage. The Cinebench results, however, tell a different story. In Cinebench R23 multicore, the Ryzen 5 8645HS actually wins with 13,220 points against the Ryzen 7's 13,082, a 1% lead. The same happens in Cinebench R15 multicore, where the 8645HS scores 2,094 versus 2,045, a 2.3% edge. This is counterintuitive given the core deficit, but it indicates that the 8645HS's higher base clock of 4.30 GHz compared to 3.30 GHz helps it in certain short-duration, all-core workloads.

Single-core performance is nearly a tie. In Cinebench R15 single-core, both chips score exactly 270, with the winner listed as the Ryzen 7 due to a 0% delta. In Cinebench R23 single-core, the 8840HS takes a slight lead with 1,737 versus 1,714, a 1.3% difference. However, in PassMark single-thread, the 8645HS edges ahead with 3,653 versus 3,626, a 0.7% margin. These results confirm that per-core performance is essentially equivalent, with the 8645HS having a negligible edge in some tests.

The remaining wins for the 8645HS are minor. In PassMark physics, the 8840HS leads 1,149 to 1,095, a 4.9% difference. In PassMark extended instructions, the 8840HS wins 20,714 to 20,003, a 3.6% margin. In PassMark find prime numbers, the 8840HS scores 79 versus 75, a 5.3% lead. Overall, the 8840HS is the clear winner in 11 of 15 comparisons, but the 8645HS's surprising Cinebench multicore victories and slight single-thread edge complicate the picture.

Architecture Differences

Both processors are built on the same Zen 4 architecture and share the Hawk Point codename, but they differ in core configuration. The Ryzen 7 8840HS has 8 cores and 16 threads, while the Ryzen 5 8645HS has 6 cores and 12 threads. This is the fundamental architectural difference that drives most of the performance gap. The cache hierarchy is identical: both have 64 KB of L1 cache per core, 1 MB of L2 cache per core, and 16 MB of shared L3 cache. No 3D V-Cache is present on either chip.

The base clock speeds differ significantly. The 8840HS runs at 3.30 GHz base, while the 8645HS runs at 4.30 GHz base—a full 1 GHz difference. Boost clocks are closer, with the 8840HS hitting 5.10 GHz and the 8645HS reaching 5.00 GHz. This explains why the 8645HS can win some multicore tests despite fewer cores: it starts from a much higher baseline frequency. The TDP also differs, with the 8840HS rated at 28 W and the 8645HS at 45 W, which likely contributes to the 8645HS's ability to sustain higher clocks under load.

The integrated graphics differ as well. The 8840HS features the Radeon 780M, while the 8645HS has the Radeon 760M. No benchmark data is provided for these iGPUs, so their relative performance is not quantified here. Both chips support DDR5 memory with dual-channel configuration and 89.6 GB/s bandwidth, use the AMD Socket FP8, and offer PCIe Gen 4 with 20 lanes (CPU only). Neither supports ECC memory, and both are unlocked multipliers—meaning they cannot be manually overclocked. They share the same 4 nm process node, foundry (TSMC), and die size of 178 mm².

Where Each One Wins

The Ryzen 7 8840HS is the clear winner for CPU-intensive parallel workloads. Its 24.4% lead in integer math and 17.3% lead in floating-point math make it the better choice for video rendering, 3D modeling, scientific simulations, and any application that scales well with core count. The 10.6% advantage in PassMark multithread reinforces this, as does the 10.3% lead in data compression and 13.2% lead in data encryption. If your work involves heavy multitasking, virtual machines, or compiling code, the 8840HS's extra two cores and four threads provide a measurable benefit.

The Ryzen 5 8645HS wins in a narrower set of scenarios. Its Cinebench R23 and R15 multicore victories, while small (1% and 2.3% respectively), suggest it can outperform the 8840HS in certain all-core rendering tasks that are sensitive to clock speed rather than core count. Its higher base clock of 4.30 GHz gives it an edge in workloads that don't scale perfectly with threads. The 8645HS also wins the PassMark single-thread test by a tiny 0.7% margin, making it marginally better for lightly-threaded applications like older games or single-threaded productivity tools.

For everyday use, the difference is minimal. Both chips have nearly identical single-core performance, so web browsing, office applications, and general desktop responsiveness will feel the same. The 8840HS's lower TDP of 28 W versus 45 W means it may be more efficient in thin-and-light laptops, potentially leading to better battery life, though this is not directly measured in the benchmark data. The 8645HS, with its higher TDP and base clock, might be better suited to thicker laptops with better cooling.

Specification Differences

• Cores: 8 (8840HS) vs 6 (8645HS)
• Threads: 16 (8840HS) vs 12 (8645HS)
• Base Clock: 3.30 GHz (8840HS) vs 4.30 GHz (8645HS)
• Boost Clock: 5.10 GHz (8840HS) vs 5.00 GHz (8645HS)
• TDP: 28 W (8840HS) vs 45 W (8645HS)
• Integrated Graphics: Radeon 780M (8840HS) vs Radeon 760M (8645HS)
• Part Number: 100-000001372(FP7r2), 100-000001379(FP7), 100-000001357(FP8) for 8840HS vs 100-000001320(FP7r2), 100-000001385(FP7), 100-000001310(FP8) for 8645HS

Everything else—including L1, L2, and L3 cache sizes, memory support, memory bus, memory bandwidth, PCIe lanes, socket, process node, transistor count, die size, and release date—is identical between the two.

FAQ

Q: Which CPU has more cores?

A: The AMD Ryzen 7 8840HS has 8 cores and 16 threads, while the AMD Ryzen 5 8645HS has 6 cores and 12 threads.

Q: Why does the Ryzen 5 8645HS win some multicore benchmarks despite having fewer cores?

A: The 8645HS has a base clock of 4.30 GHz compared to the 8840HS's 3.30 GHz. This higher base frequency allows it to edge ahead in Cinebench R23 multicore (13,220 vs 13,082) and Cinebench R15 multicore (2,094 vs 2,045), even with two fewer cores.

Q: Is there a difference in single-core performance?

A: The data shows a near tie. In Cinebench R15 single-core, both score exactly 270. In Cinebench R23 single-core, the 8840HS leads with 1,737 vs 1,714 (1.3% higher). In PassMark single-thread, the 8645HS leads with 3,653 vs 3,626 (0.7% higher).

Q: Which CPU is better for math-heavy workloads?

A: The Ryzen 7 8840HS is significantly better. It leads by 24.4% in PassMark integer math (90,382 vs 72,640) and by 17.3% in floating-point math (52,582 vs 44,833).

Q: Do both CPUs have the same cache?

A: Yes. 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 3D V-Cache.

Q: What are the TDP differences?

A: The Ryzen 7 8840HS has a TDP of 28 W, while the Ryzen 5 8645HS has a TDP of 45 W. This means the 8645HS is rated for higher power consumption, which likely explains its higher base clock.

The Verdict

Based strictly on the benchmark data, the AMD Ryzen 7 8840HS is the superior processor for most workloads. It wins 11 of 15 head-to-head tests, with decisive victories in integer math (24.4% lead), floating-point math (17.3% lead), data encryption (13.2% lead), and multithread performance (10.6% lead). Its 8 cores and 16 threads provide a substantial advantage in parallel tasks, and its lower TDP of 28 W makes it a more efficient choice for mobile devices. The 8840HS also has the Radeon 780M integrated graphics, while the 8645HS has the Radeon 760M, though no iGPU benchmarks are available in this data.

The AMD Ryzen 5 8645HS is not without merit. Its higher base clock of 4.30 GHz gives it unexpected wins in Cinebench R23 multicore (13,220 vs 13,082) and Cinebench R15 multicore (2,094 vs 2,045), suggesting it handles certain all-core rendering tasks better. Its single-thread performance is also marginally better in PassMark (3,653 vs 3,626). However, these wins are small and confined to specific tests. The 8645HS's 45 W TDP means it draws more power, which could be a drawback in thin laptops.

Choose the Ryzen 7 8840HS if you need maximum multi-core throughput for CPU-heavy applications like video editing, 3D rendering, or data processing. Its 24.4% lead in integer math and 17.3% lead in floating-point math are too significant to ignore. Choose the Ryzen 5 8645HS if you prioritize the slightly better single-thread score (0.7% in PassMark) or if your specific rendering workload benefits from higher base clocks, as evidenced by its Cinebench multicore victories. For general use, the two are nearly identical in single-core performance, so the extra cores of the 8840HS make it the safer recommendation for future-proofing. The data consistently favors the 8840HS, especially in scenarios where core count matters.