AMD EPYC 4585PX vs AMD Ryzen 9 9955HX3D Comparison

The AMD EPYC 4585PX and the AMD Ryzen 9 9955HX3D are both 16-core, 32-thread Zen 5 processors, but they target vastly different market segments: one is a server/workstation part, the other a mobile flagship. The benchmark data reveals a consistent, though not always massive, performance advantage for the EPYC 4585PX across every single test recorded. With 15 wins out of 15 head-to-head comparisons, the EPYC 4585PX establishes a clear performance hierarchy, but the magnitude of that lead varies dramatically depending on the workload, which makes the choice between them far more nuanced than a simple tally of victories.

Head-to-Head Benchmarks

The most striking victories for the AMD EPYC 4585PX come in the Cinebench single-core tests. In Cinebench R23 single-core, the EPYC 4585PX scores 8534, which is a staggering 295.2% higher than the Ryzen 9 9955HX3D’s 2159.5. Similarly, in Cinebench R15 single-core, the EPYC's 860 score eclipses the Ryzen's 332 by a 159% margin. This is the single largest performance gap in the entire dataset, suggesting that while both chips are based on the same Zen 5 architecture, the EPYC 4585PX is operating at a significantly higher clock speed or with a more favorable power envelope for single-threaded bursts. The data implies a massive difference in raw per-core throughput.

Multi-core performance also heavily favors the EPYC 4585PX, though the margin is narrower. In Cinebench R23 multi-core, the EPYC 4585PX scores 60451, a 58.4% advantage over the Ryzen 9's 38161.5. The Cinebench R15 multi-core test shows a much closer race, with the EPYC 4585PX winning by just 0.8% (6093 vs 6042.5). This suggests that the Ryzen 9 9955HX3D, despite its much lower base clock of 2.50 GHz, can sustain high multi-threaded performance, likely due to its boost clock of 5.40 GHz, but it hits a thermal or power wall that the EPYC, with its 170W TDP, does not encounter in sustained workloads.

The PassMark suite tells a story of consistent, moderate wins for the EPYC 4585PX in everyday and server-relevant tasks. In integer math, the EPYC 4585PX scores 248563, an 11.7% lead over the Ryzen's 222503. The gap shrinks in floating-point math, where the EPYC 4585PX leads by 6.3% (153219 vs 144122). Data compression shows a 12.6% advantage for the EPYC 4585PX (884774 vs 785811), while data encryption shows a 19.7% lead (47224 vs 39446). These results indicate that the EPYC 4585PX is consistently faster across the board, but the differences are less dramatic than in the synthetic Cinebench single-core tests.

Some of the most interesting data points are the smaller margins. In PassMark single-thread, the EPYC 4585PX wins by only 0.6% (4538 vs 4511). This is a surprisingly close result given the massive Cinebench single-core difference. The PassMark physics test shows a 41.1% win for the EPYC 4585PX (6612 vs 4687), while the find prime numbers test is extremely close, with the EPYC 4585PX winning by just 4.2% (547 vs 525). The EPYC 4585PX also shows a 14% lead in random string sorting (95210 vs 83497) and a 10.6% lead in extended instructions (69457 vs 62813). The data suggests that while the EPYC 4585PX is the clear winner, the Ryzen 9 9955HX3D is not a slouch, particularly in short, bursty workloads.

FAQ

Q: Is the AMD EPYC 4585PX faster than the Ryzen 9 9955HX3D in every benchmark?

A: Yes. The head-to-head data shows the EPYC 4585PX winning all 15 recorded benchmarks, with no wins for the Ryzen 9 9955HX3D.

Q: What is the biggest performance difference between the two?

A: The largest gap is in Cinebench R23 single-core, where the EPYC 4585PX is 295.2% faster. The Cinebench R15 single-core test shows a similar, though smaller, 159% advantage.

Q: How do they compare in multi-core workloads?

A: The EPYC 4585PX wins in multi-core, but the margin varies. In Cinebench R23 multi-core, it is 58.4% faster, while in Cinebench R15 multi-core, the lead is a much slimmer 0.8%.

Q: Are they similar in single-threaded performance?

A: It depends on the test. The EPYC 4585PX has a massive lead in Cinebench single-core tests, but in PassMark single-thread, the difference is just 0.6%, making them nearly identical in that specific workload.

Q: Which CPU has a higher boost clock?

A: The AMD EPYC 4585PX has a boost clock of 5.70 GHz, while the AMD Ryzen 9 9955HX3D has a boost clock of 5.40 GHz.

Q: What is the average benchmark score difference between them?

A: The EPYC 4585PX has an average benchmark score of 99324, which is 1.9% higher than the Ryzen 9 9955HX3D's average score of 97453.

Where Each One Wins

The AMD EPYC 4585PX wins in every measured category, but its dominance is concentrated in specific areas. It is the clear choice for workloads that demand maximum single-thread performance, as demonstrated by its colossal leads in Cinebench R23 and R15 single-core tests. Its 170W TDP and higher base clock of 4.30 GHz allow it to sustain high performance in longer, multi-threaded server tasks, as shown by its 58.4% win in Cinebench R23 multi-core and a 41.1% win in PassMark physics. For data-heavy server operations like data compression (12.6% win) and encryption (19.7% win), the EPYC 4585PX is also the stronger performer.

The AMD Ryzen 9 9955HX3D, despite losing all benchmarks, shows its strengths in the areas where the gap is smallest. Its performance in PassMark single-thread is nearly identical to the EPYC 4585PX, with just a 0.6% difference. This indicates that for short, single-threaded tasks, the user experience would be very similar. The extremely close result in Cinebench R15 multi-core (0.8% difference) and PassMark find prime numbers (4.2% difference) suggests that the Ryzen 9 9955HX3D can hold its own in lighter multi-threaded workloads. With its 55W TDP, it is the only one of the two that is realistically suited for a mobile, battery-powered environment, where sustained peak performance is not possible. The data shows it is a highly capable processor that sacrifices some peak performance for a dramatically lower power envelope.

Specification Differences

The two CPUs diverge significantly in their specifications despite sharing the same core architecture. The most obvious difference is the socket: the EPYC 4585PX uses AMD Socket AM5, while the Ryzen 9 9955HX3D uses AMD Socket FL1. This immediately dictates their intended platforms, with the former for desktop/workstation motherboards and the latter for laptops. Clock speeds also differ substantially, with the EPYC 4585PX having a much higher base clock of 4.30 GHz compared to the Ryzen 9's 2.50 GHz. The boost clocks are closer, with the EPYC 4585PX at 5.70 GHz and the Ryzen 9 at 5.40 GHz.

The power envelopes are vastly different, with the EPYC 4585PX having a TDP of 170W and the Ryzen 9 9955HX3D having a TDP of only 55W. The PCIe lane count differs, with the EPYC 4585PX offering 24 CPU-only lanes and the Ryzen 9 9955HX3D offering 28. The integrated graphics are also different: the EPYC 4585PX features Radeon Graphics, while the Ryzen 9 9955HX3D features a Radeon 610M. The EPYC 4585PX is not multiplier unlocked, while the Ryzen 9 9955HX3D is multiplier unlocked. Finally, the EPYC 4585PX has a launch MSRP of $699, while the Ryzen 9 has no listed launch MSRP. Both support DDR5 memory on a dual-channel bus with the same 89.6 GB/s bandwidth, and both support ECC memory.

Architecture Differences

Architecturally, both processors are built on the same fundamental Zen 5 architecture and are manufactured by TSMC on a 4 nm process. They share the same codename family lineage in the sense that both have 16 cores, 32 threads, and identical cache structures: 80 KB of L1 cache per core, 1 MB of L2 cache per core, and a large 128 MB L3 cache. The transistor count is also identical at 16,630 million, with a die size of 2x 70.6 mm². The core architectural design is therefore the same.

The key differences lie in the platform and packaging, not the core design. The EPYC 4585PX is from the EPYC 4005 series with the codename "Grado", representing a server/workstation chip. The Ryzen 9 9955HX3D is from the 9000 series with the codename "Fire Range", representing a mobile flagship. Their market segments, "Server/Workstation" versus "Mobile", are the primary architectural differentiators. The EPYC 4585PX was released on 2025-05-12, while the Ryzen 9 9955HX3D was released earlier on 2025-01-05. The EPYC 4585PX is a server part designed for maximum throughput, while the Ryzen 9 is a mobile part designed for efficiency within a strict thermal budget.

The Verdict

The data paints a clear picture: the AMD EPYC 4585PX is the overwhelmingly faster processor. It wins every benchmark, and in several key tests, its advantage is enormous. For anyone building a workstation or server who requires the absolute maximum processing power in a single-socket system, the EPYC 4585PX is the obvious choice based on the benchmark results. Its superiority in Cinebench R23 multi-core (58.4% faster) and single-core (295.2% faster) makes it the superior part for demanding professional workloads like 3D rendering, scientific simulation, and heavy compilation.

The AMD Ryzen 9 9955HX3D, however, is not a bad processor; it is a processor for a different purpose. Its 55W TDP is a fraction of the EPYC's 170W, making it the only viable option for a high-performance laptop. The data shows it is within striking distance in some lighter tasks, such as PassMark single-thread (0.6% difference) and Cinebench R15 multi-core (0.8% difference). A user who prioritizes mobility and battery life over peak performance should choose the Ryzen 9 9955HX3D. The data suggests that in short bursts, its performance is remarkably close to the EPYC, but it will not sustain that level under prolonged, heavy loads. In summary, the EPYC 4585PX is the performance king, while the Ryzen 9 9955HX3D is the efficiency champion for mobile platforms. The choice is not about which is "better," but which is the correct tool for the intended environment.