AMD EPYC 7443P vs AMD Ryzen 9 9955HX Comparison

Head-to-Head Benchmarks

The recorded data splits these two processors into very different roles. The AMD Ryzen 9 9955HX wins 5 of the 15 head-to-head comparisons, while the AMD EPYC 7443P takes 10. The margins tell the real story. The Ryzen’s biggest win is in single-threaded performance: it scores 4393 in Passmark single-thread tests, which is 51.1% ahead of the EPYC’s 2907. That is a massive gap for any workload that relies on one or two fast cores.

The Ryzen also dominates in extended instruction workloads, scoring 57946 versus 48213, a 20.2% advantage. In floating-point math, it edges out the EPYC with 136682 versus 129932, a 5.2% win. The Cinebench R15 multicore test goes to the Ryzen as well, 5905 versus 4881, a 21% lead. That is notable because the EPYC has more cores, yet the Ryzen’s newer architecture overcomes the deficit in that specific test.

The EPYC fights back hard in most other areas. Its Cinebench R23 multicore score is 48433 versus 37159, a 23.3% lead. The single-core Cinebench R23 results are lopsided in the EPYC’s favor: 6837 versus 2174, a 68.2% margin. That looks contradictory given the Passmark single-thread result, but the data shows different workloads stress different parts of the architecture. The EPYC also wins data compression (820859 versus 731998, 10.8% ahead), data encryption (57263 versus 37330, 34.8% ahead), and integer math (232632 versus 212598, 8.6% ahead).

The closest contest is Passmark multithread, where the EPYC scores 56981 and the Ryzen 56171, a mere 1.4% difference. That is effectively a tie. The EPYC’s other wins include find prime numbers (410 versus 287, 30% ahead), physics (4748 versus 2720, 42.7% ahead), and random string sorting (95581 versus 77890, 18.5% ahead). The Ryzen’s average benchmark score is 91199, while the EPYC’s is 81661. Both sit in the 96th percentile of all CPUs, so neither is a slouch.

Architecture Differences

The Ryzen 9 9955HX is built on Zen 5 architecture with the Fire Range codename, fabricated on a 4 nm process by TSMC. It uses 16,630 million transistors across a die size of 2x 70.6 mm². The EPYC 7443P uses Zen 3 with the Milan codename, on a 7 nm process, also from TSMC. It has 16,600 million transistors across 4x 81 mm² dies. The process node difference is significant: 4 nm versus 7 nm explains much of the Ryzen’s single-thread efficiency advantage.

Core counts differ sharply. The Ryzen has 16 cores and 32 threads, while the EPYC has 24 cores and 48 threads. That gives the EPYC a 50% core and thread advantage, which shows up in its multicore wins. Cache layouts are also different. The Ryzen has 80 KB of L1 per core, 1 MB of L2 per core, and 64 MB of shared L3. The EPYC has 64 KB of L1 per core, 512 KB of L2 per core, and 128 MB of shared L3. The EPYC’s double L3 capacity helps in workloads that fit large datasets.

Memory support splits along platform lines. The Ryzen uses DDR5 with a dual-channel bus, delivering 89.6 GB/s of bandwidth. The EPYC uses DDR4 with an eight-channel bus, delivering 204.8 GB/s. That is a 2.3x bandwidth advantage for the EPYC, which matters for server-style workloads. Both support ECC memory.

PCIe connectivity is another major divider. The Ryzen offers Gen 5 with 28 lanes (CPU only). The EPYC offers Gen 4 with 128 lanes (CPU only). The EPYC has far more expansion capacity, while the Ryzen has faster per-lane bandwidth. The Ryzen includes integrated Radeon 610M graphics; the EPYC has no integrated graphics. Power envelopes are wildly different: the Ryzen has a 55 W TDP, the EPYC has a 200 W TDP. The Ryzen’s multiplier is unlocked, the EPYC’s is not.

The Ryzen uses AMD Socket FL1, while the EPYC uses AMD Socket SP3. The Ryzen was released in January 2025, the EPYC in March 2021. The Ryzen’s part number is 100-000001028, the EPYC’s is 100-000000342100-100000342WOF.

Where Each One Wins

The Ryzen 9 9955HX is the clear choice for single-thread-sensitive tasks. Its 51.1% lead in Passmark single-thread and its 5.2% win in floating-point math point to workloads like gaming, lightweight code compilation, and everyday desktop responsiveness. The 20.2% win in extended instructions suggests it handles modern SIMD-heavy applications well, including media encoding and some scientific workloads. The 21% lead in Cinebench R15 multicore is interesting because it shows that in some older multi-threaded tests, the Ryzen’s per-core speed can overcome its core count disadvantage. Its 55 W TDP makes it viable for mobile platforms, which the EPYC cannot match.

The EPYC 7443P wins where raw throughput and memory bandwidth matter. Its 23.3% lead in Cinebench R23 multicore and its 34.8% lead in data encryption are strong signals for server workloads, database operations, and virtualized environments. The 42.7% lead in physics simulation and the 30% lead in prime number finding indicate heavy compute tasks that scale with cores. The 18.5% lead in random string sorting and the 10.8% lead in data compression point to file servers, log processing, and data analytics. The eight-channel DDR4 memory, with 204.8 GB/s bandwidth, gives it a massive advantage for memory-bound applications like large in-memory databases. The 128 PCIe Gen 4 lanes allow it to drive many NVMe drives, GPUs, and network cards simultaneously.

The Passmark multithread result, a 1.4% EPYC margin, shows that for generic all-core workloads, these two are nearly interchangeable. The choice comes down to whether you need the Ryzen’s speed per thread or the EPYC’s scale in cores and memory.

FAQ

Q: Which processor has better single-core performance?

A: The Ryzen 9 9955HX wins Passmark single-thread with 4393 versus 2907, a 51.1% lead. However, the EPYC wins Cinebench R23 single-core with 6837 versus 2174, a 68.2% margin. The results depend on the benchmark and its specific instruction mix.

Q: Is the EPYC 7443P faster in multi-core workloads overall?

A: Yes, in most multicore tests. It wins Cinebench R23 multicore by 23.3%, data compression by 10.8%, and integer math by 8.6%. The Ryzen wins Cinebench R15 multicore by 21%, but the EPYC takes the majority of multicore comparisons.

Q: Can the Ryzen 9 9955HX replace the EPYC 7443P in a server?

A: No, not directly. The EPYC has 24 cores versus 16, 128 MB L3 versus 64 MB, and 204.8 GB/s memory bandwidth versus 89.6 GB/s. The EPYC also supports 128 PCIe Gen 4 lanes versus the Ryzen’s 28 Gen 5 lanes. The Ryzen is designed for mobile, the EPYC for server/workstation.

Q: Which processor has better memory bandwidth?

A: The EPYC 7443P by a wide margin. It uses eight-channel DDR4 with 204.8 GB/s bandwidth. The Ryzen uses dual-channel DDR5 with 89.6 GB/s. That is a 2.3x difference in favor of the EPYC.

Q: Do both processors support ECC memory?

A: Yes, both have ECC memory support. This is unusual for the Ryzen, which is a mobile part, but the data confirms it.

Q: What are the power consumption differences?

A: The Ryzen 9 9955HX has a 55 W TDP. The EPYC 7443P has a 200 W TDP. The EPYC uses nearly four times the power, which is consistent with its server-class design and higher core count.

Specification Differences

| Specification | AMD Ryzen 9 9955HX | AMD EPYC 7443P |

|---|---|---|

| Cores | 16 | 24 |

| Threads | 32 | 48 |

| Base Clock | 2.50 GHz | 2.85 GHz |

| Boost Clock | 5.40 GHz | 4.00 GHz |

| TDP | 55 W | 200 W |

| Socket | AMD Socket FL1 | AMD Socket SP3 |

| Architecture | Zen 5 | Zen 3 |

| Codename | Fire Range | Milan |

| Process Node | 4 nm | 7 nm |

| Transistors | 16,630 million | 16,600 million |

| Die Size | 2x 70.6 mm² | 4x 81 mm² |

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

| L2 Cache | 1 MB (per core) | 512 KB (per core) |

| L3 Cache | 64 MB (shared) | 128 MB (shared) |

| Memory Support | DDR5 | DDR4 |

| Memory Bus | Dual-channel | Eight-channel |

| Memory Bandwidth | 89.6 GB/s | 204.8 GB/s |

| PCIe | Gen 5, 28 Lanes | Gen 4, 128 Lanes |

| Integrated Graphics | Radeon 610M | None |

| Market Segment | Mobile | Server/Workstation |

| Release Date | 2025-01-05 | 2021-03-14 |

| Launch MSRP | None listed | $1337 |

| Multiplier Unlocked | Yes | No |

| Part Number | 100-000001028 | 100-000000342100-100000342WOF |

The Verdict

Choose the AMD Ryzen 9 9955HX if your priority is single-thread speed in a low-power mobile package. The data shows a 51.1% lead in Passmark single-thread and a 20.2% lead in extended instructions. Its 55 W TDP and integrated Radeon 610M graphics make it a complete mobile solution. The unlocked multiplier adds flexibility for enthusiasts. It wins in floating-point math and Cinebench R15 multicore, so it handles mixed workloads with surprising agility. Its 5.40 GHz boost clock is the highest in this comparison, and the 4 nm process gives it a clear efficiency edge.

Choose the AMD EPYC 7443P if you need maximum core count, memory bandwidth, and expansion capacity. Its 24 cores and 48 threads, combined with 128 MB of L3 and 204.8 GB/s of memory bandwidth, make it the right tool for server-class workloads. The 23.3% lead in Cinebench R23 multicore, 34.8% lead in encryption, and 42.7% lead in physics simulation are decisive. The 128 PCIe Gen 4 lanes allow massive I/O configurations. The 200 W TDP is a non-issue in a server chassis. The launch MSRP of $1337 reflects its professional positioning.

The average benchmark scores tell a similar story: the Ryzen averages 91199, the EPYC averages 81661, but both sit in the 96th percentile. The Ryzen is the better all-around performer for interactive and latency-sensitive tasks. The EPYC is the better brute-force compute engine. If you are building a laptop or a compact workstation, the Ryzen is the obvious pick. If you are populating a rack or a workstation that needs heavy memory throughput and many PCIe devices, the EPYC is the data-backed choice. There is no single correct answer; the recorded results point to two different machines for two different jobs.