AMD Ryzen 5 7645HX vs AMD Ryzen 7 3700X Comparison

The AMD Ryzen 7 3700X and AMD Ryzen 5 7645HX represent two distinct generations and market segments of AMD’s processor lineup. The 3700X is a desktop-class 3000-series part built on Zen 2, while the 7645HX is a mobile-focused 7000-series chip using Zen 4. Despite the older platform and lower core count of the latter, benchmark data shows a decisive performance shift toward the newer architecture, with the 7645HX winning 14 of 15 head-to-head comparisons. The single exception is a narrow victory for the 3700X in data encryption, making that the only workload where the desktop part retains an advantage. Both processors sit at the 84th percentile among all CPUs, yet their average benchmark scores differ by only 592 points, suggesting that overall performance is close even as the distribution of wins is lopsided.

Where Each One Wins

The performance split is overwhelmingly in favor of the AMD Ryzen 5 7645HX across nearly every measured workload. The 7645HX leads in all multi-threaded and single-threaded application benchmarks, including Cinebench R15 multi-core (2276 vs 2092), Geekbench multi-core (11586 vs 8899), and every PassMark test category except data encryption. This includes substantial margins in integer math (77432 vs 66399), floating-point math (48798 vs 39005), and extended instructions (22969 vs 19241). The 7645HX also wins in memory-sensitive tasks like random string sorting (34434 vs 32131) and data compression (302256 vs 296379), albeit with smaller deltas of 6.7% and 1.9%, respectively.

The AMD Ryzen 7 3700X has exactly one win: PassMark data encryption, where it scores 18900 against the 7645HX’s 17900, a 5.6% advantage. This is a narrow but real edge, likely tied to its higher thread count (16 vs 12) and older architecture’s encryption throughput characteristics. No other benchmark in the data set favors the 3700X. For users whose primary workloads involve cryptographic operations or data encoding, the 3700X retains a specific, measurable benefit. For all other tasks—rendering, general productivity, scientific computing, and even compression—the 7645HX is the stronger performer, often by double-digit percentages.

Architecture Differences

The two chips diverge fundamentally in architecture, process node, and platform support. The Ryzen 7 3700X uses the Zen 2 architecture on TSMC’s 7 nm process, with a die size of 74 mm² and 3,800 million transistors. It features 8 cores and 16 threads, with base and boost clocks of 3.60 GHz and 4.40 GHz, respectively. The 7645HX is a Zen 4 part built on TSMC’s 5 nm node, packing 6,570 million transistors into a slightly smaller 71 mm² die. It offers 6 cores and 12 threads, but clocks substantially higher at 4.00 GHz base and 5.00 GHz boost. The 7645HX also doubles the L2 cache per core (1 MB vs 512 KB), while both share 32 MB of L3 cache, though the 7645HX’s is shared across the chip rather than per-CCX.

Memory and I/O capabilities also differ sharply. The 3700X supports DDR4 with dual-channel memory bandwidth of 51.2 GB/s, while the 7645HX moves to DDR5 with 83.2 GB/s—a 62.5% increase in theoretical bandwidth. The 7645HX also supports ECC memory, which the 3700X does not. PCIe connectivity is another generational leap: the 3700X offers Gen 4 with 24 lanes, while the 7645HX provides Gen 5 with 28 lanes. The 7645HX includes integrated Radeon 610M graphics, whereas the 3700X has no integrated GPU. The 7645HX is a mobile part on AMD Socket FL1 with a 45 W TDP, compared to the 3700X’s 65 W TDP on AMD Socket AM4. Notably, the 3700X has an unlocked multiplier and a launch MSRP of $329, while the 7645HX is locked and has no listed launch MSRP.

Head-to-Head Benchmarks

The largest margin in any single test belongs to the 7645HX in Geekbench single-core, where it scores 2657 against the 3700X’s 1593, a 40% advantage. This is the clearest expression of the Zen 4 IPC and clock speed gains over Zen 2. Cinebench R15 single-core shows a similar pattern, with the 7645HX leading 289 vs 204, a 29.4% delta. PassMark single-thread results confirm the trend: 3907 vs 2656, a 32% gap. These single-threaded wins are consistent across all three benchmark suites, indicating that the 7645HX’s higher boost clock and newer core design translate directly into faster per-thread execution.

In multi-threaded workloads, the 7645HX wins despite having 2 fewer cores and 4 fewer threads. Geekbench multi-core shows 11586 vs 8899, a 23.2% lead. Cinebench R15 multi-core is closer at 2276 vs 2092, an 8.1% edge, likely due to the 3700X’s extra cores partially offsetting the IPC deficit. PassMark multi-thread scoring has the 7645HX ahead at 26476 vs 22458, a 15.2% margin. The pattern repeats in PassMark physics (1497 vs 1181, 21.1% delta) and find prime numbers (178 vs 99, 44.4% delta), where the 7645HX’s per-core efficiency dominates. The only test the 3700X wins is data encryption at 18900 vs 17900, a 5.6% margin, which stands as an outlier against the otherwise universal 7645HX superiority.

The Verdict

The benchmark data is unambiguous: the AMD Ryzen 5 7645HX is the superior processor for virtually all workloads, despite having fewer cores and threads. Its wins span single-core, multi-core, integer, floating-point, and extended instruction workloads, with margins ranging from 1.9% in data compression to 40% in Geekbench single-core. The 7645HX’s higher clock speeds (4.00/5.00 GHz vs 3.60/4.40 GHz) and newer Zen 4 architecture on a 5 nm process allow it to outperform the 3700X’s 8-core/16-thread configuration in most multi-threaded tests, a remarkable result for a 6-core/12-thread mobile chip. The 3700X’s single win in data encryption suggests it may still be relevant for specific cryptographic workloads, but its 5.6% edge there is far smaller than the 7645HX’s double-digit leads elsewhere.

For users deciding between these two, the choice depends on the priority of that one encryption workload versus everything else. If the primary task is data encryption, the 3700X offers a measurable, albeit modest, advantage. For any other application—rendering, code compilation, scientific simulation, or general productivity—the 7645HX is the clear pick, delivering 8% to 44% higher performance depending on the test. The 7645HX also brings modern platform features: DDR5 memory support with 83.2 GB/s bandwidth, PCIe Gen 5 with 28 lanes, integrated Radeon 610M graphics, and ECC memory capability. The 3700X counters with an unlocked multiplier and a lower 65 W TDP, but its DDR4 support and lack of integrated graphics are drawbacks for new builds. Given the data, the 7645HX is the recommended processor for most users, with the 3700X reserved for those who specifically need its encryption throughput.

FAQ

Q: Which processor is faster in single-core performance?

A: The AMD Ryzen 5 7645HX wins all single-core tests by wide margins. It scores 2657 in Geekbench single-core vs 1593 for the 3700X (40% faster), 289 vs 204 in Cinebench R15 single-core (29.4% faster), and 3907 vs 2656 in PassMark single-thread (32% faster).

Q: Does the 3700X beat the 7645HX in any benchmark?

A: Yes, the 3700X wins exactly one test: PassMark data encryption, where it scores 18900 against the 7645HX’s 17900, a 5.6% advantage. This is the only head-to-head comparison out of 15 where the 3700X comes out ahead.

Q: How does the 7645HX outperform the 3700X in multi-threaded tests despite having fewer cores?

A: The 7645HX has 6 cores and 12 threads compared to the 3700X’s 8 cores and 16 threads, but it still leads in multi-threaded benchmarks. It wins Cinebench R15 multi-core 2276 vs 2092 (8.1% faster), Geekbench multi-core 11586 vs 8899 (23.2% faster), and PassMark multi-thread 26476 vs 22458 (15.2% faster). This is attributable to its higher boost clock (5.00 GHz vs 4.40 GHz) and newer Zen 4 architecture.

Q: What are the key memory and I/O differences between the two?

A: The 3700X supports DDR4 with 51.2 GB/s dual-channel bandwidth, while the 7645HX supports DDR5 with 83.2 GB/s. The 7645HX also offers ECC memory support, PCIe Gen 5 with 28 lanes, and integrated Radeon 610M graphics. The 3700X has PCIe Gen 4 with 24 lanes and no integrated graphics.

Q: Which processor has a higher power draw?

A: The 3700X has a higher TDP at 65 W compared to the 7645HX’s 45 W. The 7645HX is a mobile processor on AMD Socket FL1, while the 3700X is a desktop part on AMD Socket AM4.

Q: Is the 3700X’s cache configuration different from the 7645HX?

A: Both have 64 KB of L1 cache per core and 32 MB of L3 cache, but the L2 cache differs. The 3700X has 512 KB of L2 per core, while the 7645HX has 1 MB per core, doubling the L2 capacity. The 3700X’s L3 is not specified as shared, whereas the 7645HX’s 32 MB is explicitly shared.