AMD Ryzen 7 8745HX vs AMD Ryzen 9 9900X Comparison

The AMD Ryzen 7 8745HX and AMD Ryzen 9 9900X are both active AMD processors, but they target different platforms. The 8745HX is a mobile chip for Socket FL1, while the 9900X is a desktop chip for Socket AM5. The database contains 11 shared PassMark benchmarks, and the results are one-sided: the Ryzen 9 9900X wins every test, with deltas ranging from 17% to 63.5%.

The Verdict

The benchmark data is decisive. The Ryzen 9 9900X wins all 11 shared PassMark tests, with the largest margin in prime number finding (63.5% faster) and the smallest in single-thread performance (17% faster). The 8745HX, however, is a mobile processor with a 55 W TDP and an FL1 socket, while the 9900X is a desktop part with a 120 W TDP and an AM5 socket. Therefore, the 9900X is the right choice for any desktop build where performance is the priority, and the 8745HX is the only one of the two that can be used in a mobile platform. Both processors sit at the 92nd percentile of all CPUs in the database, but that overall ranking does not reflect the head-to-head results, which are unambiguous.

FAQ

Q: Which processor has more cores and threads?

A: The Ryzen 9 9900X has 12 cores and 24 threads, while the Ryzen 7 8745HX has 8 cores and 16 threads.

Q: What is the difference in boost clock?

A: The 9900X boosts to 5.60 GHz, the 8745HX to 5.10 GHz.

Q: Which has larger L3 cache?

A: The 9900X has 64 MB of L3 cache, the 8745HX has 32 MB.

Q: Does either support ECC memory?

A: The 9900X supports ECC memory, the 8745HX does not.

Q: Which has higher memory bandwidth?

A: The 9900X has 89.6 GB/s, the 8745HX has 83.2 GB/s.

Q: What is the process node difference?

A: The 9900X is built on TSMC's 4 nm process, the 8745HX on 5 nm.

Architecture Differences

Architecturally, the two processors are from different generations and microarchitectures. The 8745HX uses Zen 4 (Dragon Range) on a 5 nm process, while the 9900X uses Zen 5 (Granite Ridge) on a 4 nm process. The 9900X integrates 16,630 million transistors across two 70.6 mm² dies, whereas the 8745HX has 6,570 million transistors on a single 71 mm² die. The L1 cache per core is larger on the 9900X (80 KB vs 64 KB), and the L3 cache is double (64 MB vs 32 MB). The 9900X also supports ECC memory, which the 8745HX does not. The integrated graphics differ: the 8745HX has a Radeon 610M, while the 9900X has a generic Radeon Graphics. The 9900X has 24 PCIe Gen 5 lanes, the 8745HX has 28. The 8745HX is a mobile part with a 55 W TDP, the 9900X a desktop part with 120 W. The 9900X has a higher base clock (4.40 vs 3.60 GHz) and boost clock (5.60 vs 5.10 GHz).

Specification Differences

| Specification | Ryzen 7 8745HX | Ryzen 9 9900X |

| Cores | 8 | 12 |

| Threads | 16 | 24 |

| Base clock | 3.60 GHz | 4.40 GHz |

| Boost clock | 5.10 GHz | 5.60 GHz |

| TDP | 55 W | 120 W |

| Socket | AMD Socket FL1 | AMD Socket AM5 |

| Architecture | Zen 4 | Zen 5 |

| Codename | Dragon Range | Granite Ridge |

| Process node | 5 nm | 4 nm |

| Transistors | 6,570 million | 16,630 million |

| Die size | 71 mm² | 2x 70.6 mm² |

| L1 cache (per core) | 64 KB | 80 KB |

| L3 cache | 32 MB | 64 MB |

| Memory bandwidth | 83.2 GB/s | 89.6 GB/s |

| ECC memory | No | Yes |

| PCIe lanes | 28 | 24 |

| Integrated graphics | Radeon 610M | Radeon Graphics |

| Market segment | Mobile | Desktop |

| Release date | 2025-04-22 | 2024-08-14 |

| Launch MSRP | None | $499 |

Head-to-Head Benchmarks

All 11 shared PassMark benchmarks are won by the Ryzen 9 9900X. The largest margin is in passmark_find_prime_numbers, where the 9900X scores 436 versus 159, a 63.5% advantage. The physics test shows a 50.3% gap (3381 vs 1681). Extended instructions are exactly 50% higher (55243 vs 27638). Floating point math is 48.4% ahead (120083 vs 61972). Data compression is 46.8% faster (683579 vs 363759). Integer math is 44.6% ahead (181056 vs 100328). Multithread performance is 42.3% higher (54643 vs 31517). Random string sorting is 38.2% faster (72013 vs 44494). Data encryption is 34.7% ahead (33421 vs 21840). The smallest gap is in single-thread performance, where the 9900X leads by 17% (4672 vs 3879). The 8745HX does not win any of the 11 tests. The single-thread delta is the narrowest, indicating that the 8745HX is relatively stronger in lightly threaded workloads, but it still trails. The multithread and specialized workload gaps are large, consistent with the 9900X's higher core count, higher clocks, and larger caches.