AMD EPYC 4345P vs AMD Ryzen 9 3900 Comparison

The AMD EPYC 4345P and AMD Ryzen 9 3900 are both 65W AMD processors, but they target different eras and use cases. The EPYC 4345P is a modern Zen 5 server chip on the AM5 socket, while the Ryzen 9 3900 is a Zen 2 desktop chip on AM4. In head-to-head benchmarks, the EPYC 4345P wins 11 of 13 tests, including all multi-threaded workloads, despite having only 8 cores and 16 threads versus the Ryzen’s 12 cores and 24 threads. The Ryzen 9 3900 does claim two wins in niche workloads, but the overall data points decisively toward the EPYC for anyone who can use its platform features.

The Verdict

The AMD EPYC 4345P is the clear performance winner for nearly every workload in the data. It beats the Ryzen 9 3900 in multi-core Cinebench R15 by 15.1% (3227 vs 2804), and the margin grows to 30.9% in PassMark floating point math (74255 vs 56730) and 26.7% in integer math (123774 vs 97698). For single-thread performance, the EPYC is in another league entirely, scoring 4408 in PassMark single-thread versus 2604 for the Ryzen, a 69.3% advantage. The Ryzen 9 3900’s only wins are PassMark data encryption (26657 vs 23313, a 12.5% edge) and PassMark find prime numbers (203 vs 167, a 17.7% edge). If you need raw compute throughput, the EPYC 4345P is the pick. Choose the Ryzen 9 3900 only if your specific workload is dominated by prime-number finding or data encryption, or if you require the AM4 platform with its unlocked multiplier. The EPYC 4345P is not multiplier-unlocked, so it lacks that overclocking flexibility.

Architecture Differences

The EPYC 4345P is built on the Zen 5 architecture (codenamed Grado) using a 4nm TSMC process, while the Ryzen 9 3900 uses Zen 2 (codenamed Matisse) on a 7nm TSMC process. This process advantage is a major factor in the EPYC’s single-thread dominance. The EPYC packs 8,315 million transistors on a 70.6 mm² die; the Ryzen has 7,600 million transistors spread across two 74 mm² dies. Core counts differ: the EPYC has 8 cores and 16 threads, while the Ryzen has 12 cores and 24 threads. Despite having fewer cores, the EPYC wins multi-threaded tests, showing the efficiency of Zen 5. Cache layouts also differ: the EPYC provides 80 KB L1 and 1 MB L2 per core with 32 MB shared L3, while the Ryzen offers 64 KB L1 and 512 KB L2 per core with a larger 64 MB L3. The EPYC supports DDR5 memory with 89.6 GB/s bandwidth, while the Ryzen uses DDR4 with 51.2 GB/s. The EPYC also has integrated Radeon Graphics, whereas the Ryzen has none. PCIe generation differs: the EPYC uses Gen 5 with 24 CPU lanes, the Ryzen uses Gen 4 with 24 lanes. The EPYC supports ECC memory; the Ryzen does not.

Head-to-Head Benchmarks

The EPYC 4345P’s biggest win is in Cinebench R15 single-core, where it scores 455 versus the Ryzen’s 197, a massive 131% lead. This reflects the generational leap in IPC and clock speed. The EPYC’s boost clock is 5.50 GHz versus the Ryzen’s 4.30 GHz, and its base clock is 3.80 GHz versus 3.10 GHz. In PassMark physics, the EPYC scores 2583 against 1617, a 59.7% advantage, indicating stronger per-core computational efficiency. The EPYC also leads in PassMark multithread (36123 vs 30586, 18.1% higher) and extended instructions (31663 vs 26073, 21.4% higher). The Ryzen 9 3900 fights back in PassMark find prime numbers, scoring 203 versus 167 (a 17.7% win), suggesting its larger L3 cache (64 MB vs 32 MB) helps in certain memory-latency-sensitive algorithms. In data encryption, the Ryzen wins 26657 vs 23313 (12.5% higher), which could indicate a specific instruction path advantage. The EPYC wins narrowly in data compression (421490 vs 413887, 1.8%) and random string sorting (46238 vs 44902, 3%). Overall, the EPYC’s wins are broader and larger in magnitude, while the Ryzen’s two wins are isolated to specific math operations.

Specification Differences

| Specification | AMD EPYC 4345P | AMD Ryzen 9 3900 |

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

| Cores | 8 | 12 |

| Threads | 16 | 24 |

| Base Clock | 3.80 GHz | 3.10 GHz |

| Boost Clock | 5.50 GHz | 4.30 GHz |

| Architecture | Zen 5 | Zen 2 |

| Codename | Grado | Matisse |

| Process Node | 4 nm | 7 nm |

| Transistors | 8,315 million | 7,600 million |

| Die Size | 70.6 mm² | 2x 74 mm² |

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

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

| L3 Cache | 32 MB (shared) | 64 MB |

| Memory Support | DDR5 | DDR4 |

| Memory Bandwidth | 89.6 GB/s | 51.2 GB/s |

| ECC Memory | Yes | No |

| PCIe | Gen 5, 24 Lanes | Gen 4, 24 Lanes |

| Integrated Graphics | Radeon Graphics | None |

| Socket | AMD Socket AM5 | AMD Socket AM4 |

| Multiplier Unlocked | No | Yes |

| Launch MSRP | $329 | $499 |

The table shows the EPYC is newer, faster per core, and has a lower launch MSRP. The Ryzen has more cores and a larger L3 cache, but its older architecture and slower clocks hold it back. The EPYC’s ECC support and DDR5 make it suited for server duties, while the Ryzen’s unlocked multiplier appeals to desktop overclockers. The EPYC is also smaller in die size, which contributes to its power efficiency.

FAQ

Q: Which CPU is faster in single-threaded performance?

A: The AMD EPYC 4345P is significantly faster. It scores 4408 in PassMark single-thread versus 2604 for the Ryzen 9 3900, a 69.3% lead. In Cinebench R15 single-core, the EPYC scores 455 versus 197, a 131% advantage.

Q: Does the Ryzen 9 3900 win any benchmarks at all?

A: Yes, two. It wins PassMark data encryption (26657 vs 23313, 12.5% higher) and PassMark find prime numbers (203 vs 167, 17.7% higher). These are the only two tests where the Ryzen outperforms the EPYC.

Q: How do the core counts compare, and does it matter?

A: The Ryzen 9 3900 has 12 cores and 24 threads, while the EPYC 4345P has 8 cores and 16 threads. Despite having fewer cores, the EPYC wins multi-threaded tests like Cinebench R15 (3227 vs 2804, 15.1% higher) and PassMark multithread (36123 vs 30586, 18.1% higher), thanks to its newer Zen 5 architecture.

Q: What memory types do these CPUs support?

A: The EPYC 4345P supports DDR5 memory with a dual-channel bus and 89.6 GB/s bandwidth. The Ryzen 9 3900 supports DDR4 memory with a dual-channel bus and 51.2 GB/s bandwidth. The EPYC also supports ECC memory, which the Ryzen does not.

Q: Are these CPUs on the same socket?

A: No. The EPYC 4345P uses AMD Socket AM5, while the Ryzen 9 3900 uses AMD Socket AM4. They are not interchangeable, and each requires a different motherboard platform.

Q: What is the difference in launch MSRP?

A: The EPYC 4345P has a launch MSRP of $329, while the Ryzen 9 3900 has a launch MSRP of $499. The EPYC is less expensive at launch and offers higher performance in most benchmarks.

Where Each One Wins

The AMD EPYC 4345P wins in 11 of 13 head-to-head benchmarks, making it the dominant choice for general compute, content creation, and server workloads. Its 30.9% lead in floating point math (74255 vs 56730) and 26.7% lead in integer math (123774 vs 97698) indicate strong performance in scientific computing and data processing. The 59.7% advantage in PassMark physics (2583 vs 1617) suggests better simulation and modeling performance. For single-threaded tasks like web serving or legacy applications, the 69.3% PassMark single-thread lead (4408 vs 2604) is decisive. The EPYC’s ECC memory support and DDR5 bandwidth (89.6 GB/s vs 51.2 GB/s) make it suitable for reliability-critical server roles. Its integrated Radeon Graphics provide a display output without a discrete GPU, which is useful for headless servers or basic workstation tasks.

The AMD Ryzen 9 3900 wins in exactly two benchmarks. In PassMark data encryption, it scores 26657 versus 23313, a 12.5% edge, making it the better pick for encryption-heavy operations like VPN servers or secure file storage. In PassMark find prime numbers, it scores 203 versus 167, a 17.7% edge, suggesting an advantage in certain number-theoretic computations. The Ryzen’s larger 64 MB L3 cache (versus 32 MB) may contribute to these wins by holding more working data. Additionally, the Ryzen 9 3900 has an unlocked multiplier, allowing overclocking that could narrow the gap in other tests, though the benchmark data shows it still trails in most metrics at stock settings. For desktop users who already own an AM4 motherboard and want to overclock, the Ryzen offers that flexibility. For anyone building on a modern platform, the EPYC 4345P is the superior processor based on the data.