AMD EPYC 4564P vs AMD Ryzen 9 9955HX Comparison

The AMD EPYC 4564P and AMD Ryzen 9 9955HX are both 16-core, 32-thread processors, yet they serve fundamentally different markets and deliver contrasting performance profiles. Benchmark data shows the EPYC 4564P wins 12 of the 15 head-to-head comparisons, including decisive victories in multi-core and single-core Cinebench tests, while the Ryzen 9 9955HX claims only 3 wins, all by narrow margins. Despite the Ryzen’s newer architecture, the EPYC’s higher clock speeds and server-oriented design make it the stronger performer in nearly every measurable workload, though the Ryzen’s efficiency and mobile pedigree give it a distinct role.

The Verdict

The data points to a clear split: the AMD EPYC 4564P is the choice for raw compute throughput, while the AMD Ryzen 9 9955HX serves a different purpose entirely. The EPYC leads in Cinebench R23 multi-core with a score of 55,592 against the Ryzen’s 37,159, a 49.6% advantage, and it also dominates single-core R23 at 7,848 versus 2,174, a 261% gap. These are not marginal differences; they indicate the EPYC is in a different performance class for both threaded and single-threaded tasks. PassMark multithread scores reinforce this, with the EPYC at 64,357 versus 56,171, a 14.6% lead. For anyone assembling a workstation or server where compute density and maximum throughput are priorities, the EPYC 4564P is the data-backed selection.

The Ryzen 9 9955HX, however, wins in PassMark single-thread performance, scoring 4,393 against the EPYC’s 4,292, a 2.3% edge, and also takes Cinebench R15 multi-core at 5,905 versus 5,603, a 5.1% margin. Its 55W TDP compared to the EPYC’s 170W suggests a far more power-efficient design, making it suitable for mobile workstations or compact systems where thermal and power budgets are constrained. The Ryzen’s unlocked multiplier further distinguishes it for enthusiasts who prioritize tuning. The verdict from the data is simple: pick the EPYC for maximum performance, pick the Ryzen for efficiency and flexibility in a mobile form factor.

Where Each One Wins

The EPYC 4564P wins decisively in compute-heavy and data-processing workloads. In PassMark data compression, it scores 858,105 versus 731,998, a 17.2% advantage, and in data encryption it leads with 50,708 against 37,330, a 35.8% margin. These are tasks common in server environments, database management, and secure communications. The EPYC also dominates in random string sorting, scoring 103,202 versus 77,890, a 32.5% lead, and in find prime numbers at 365 versus 287, a 27.2% gap. The pattern is consistent: the EPYC’s higher base and boost clocks (4.50 GHz and 5.70 GHz versus 2.50 GHz and 5.40 GHz) translate into superior performance across the board in PassMark’s integer, floating-point, and extended instruction tests.

The Ryzen 9 9955HX wins only in single-thread PassMark tests and one older Cinebench multi-core benchmark. Its PassMark single-thread score of 4,393 edges out the EPYC’s 4,292, a 2.3% margin, and it takes Cinebench R15 multi-core 5,905 to 5,603. These wins suggest the Ryzen’s Zen 5 architecture offers slightly better single-core efficiency in certain legacy tests, but the margins are slim. The Ryzen’s wins do not indicate overall superiority; they highlight niches where its design excels, such as lightly-threaded applications or older benchmark suites. For modern multi-core workloads, the EPYC is consistently ahead.

Architecture Differences

The two processors are built on different Zen generations and manufacturing nodes. The EPYC 4564P uses Zen 4 architecture on a 5 nm TSMC process, with a die size of 2x 71 mm² and 13,140 million transistors. The Ryzen 9 9955HX uses newer Zen 5 architecture on a 4 nm TSMC process, with a die size of 2x 70.6 mm² and 16,630 million transistors. The Ryzen’s process node is more advanced, but the EPYC compensates with significantly higher clock speeds. Cache configurations differ in L1: the EPYC has 64 KB per core, while the Ryzen has 80 KB per core; both share 64 MB of L3 cache and 1 MB of L2 per core.

The EPYC is designed for the AMD Socket AM5, while the Ryzen uses the AMD Socket FL1, reflecting their different market segments—server/workstation versus mobile. The EPYC has a 170W TDP, more than triple the Ryzen’s 55W, and it is not multiplier unlocked, whereas the Ryzen is. Both support DDR5 memory in dual-channel configurations, with the Ryzen offering slightly higher memory bandwidth at 89.6 GB/s versus 83.2 GB/s, and both support ECC memory. Integrated graphics differ: the EPYC features Radeon Graphics, while the Ryzen has the Radeon 610M. PCIe support is identical at Gen 5 with 28 lanes for both.

FAQ

Q: Which processor has better multi-core performance?

A: The EPYC 4564P is significantly faster in multi-core workloads. It scores 55,592 in Cinebench R23 multi-core versus 37,159 for the Ryzen 9 9955HX, a 49.6% advantage, and leads in PassMark multithread at 64,357 versus 56,171.

Q: Does the Ryzen 9 9955HX win in any benchmark?

A: Yes, the Ryzen wins in PassMark single-thread performance (4,393 versus 4,292, a 2.3% edge) and in Cinebench R15 multi-core (5,905 versus 5,603, a 5.1% margin). These are the only two test categories where it comes out ahead.

Q: What is the difference in power consumption?

A: The EPYC 4564P has a TDP of 170W, while the Ryzen 9 9955HX has a TDP of 55W. This makes the Ryzen far more power-efficient, though the EPYC’s higher power draw enables its superior performance.

Q: Are both processors built on the same architecture?

A: No, the EPYC uses Zen 4 architecture, while the Ryzen uses the newer Zen 5 architecture. The Ryzen is also on a more advanced 4 nm process node compared to the EPYC’s 5 nm node.

Q: Do both processors support ECC memory?

A: Yes, both the EPYC 4564P and the Ryzen 9 9955HX support ECC memory, which is unusual for a mobile processor and adds to the Ryzen’s versatility for certain professional workloads.

Q: Which processor is better for single-core performance?

A: The EPYC 4564P is dramatically better in Cinebench R23 single-core, scoring 7,848 versus 2,174 for the Ryzen, a 261% lead. However, the Ryzen edges out the EPYC in PassMark single-thread, 4,393 versus 4,292.

Head-to-Head Benchmarks

The largest win for the EPYC 4564P comes in Cinebench R23 single-core, where it scores 7,848 against the Ryzen’s 2,174, a staggering 261% delta. This is the most decisive result in the dataset and underscores the EPYC’s clock speed advantage at 5.70 GHz boost versus 5.40 GHz. Cinebench R23 multi-core also shows a massive gap, with the EPYC at 55,592 and the Ryzen at 37,159, a 49.6% difference, indicating the EPYC sustains its performance under full-thread loads far better. PassMark data encryption is another standout, with the EPYC at 50,708 versus 37,330, a 35.8% lead, and random string sorting at 103,202 versus 77,890, a 32.5% margin.

The Ryzen 9 9955HX’s wins are narrower. Its PassMark single-thread score of 4,393 is only 2.3% above the EPYC’s 4,292, and its Cinebench R15 multi-core win at 5,905 versus 5,603 is a 5.1% margin. These results suggest the Ryzen’s Zen 5 cores have a slight efficiency edge in certain legacy or lightly-threaded tests, but they do not translate into broader performance superiority. In the remaining benchmarks—PassMark data compression, extended instructions, find prime numbers, floating-point math, integer math, physics, and multithread—the EPYC wins by margins ranging from 3.2% (floating-point math at 141,017 versus 136,682) to 27.2% (find prime numbers at 365 versus 287). The overall scoreboard is 12 wins for the EPYC and 3 for the Ryzen.

Specification Differences

The two processors diverge most sharply in clock speeds, power, and socket. The EPYC 4564P has a base clock of 4.50 GHz and boost clock of 5.70 GHz, while the Ryzen 9 9955HX runs at 2.50 GHz base and 5.40 GHz boost. The EPYC’s TDP is 170W compared to the Ryzen’s 55W, and it uses AMD Socket AM5 versus the Ryzen’s AMD Socket FL1. The EPYC is not multiplier unlocked, while the Ryzen is, allowing for user overclocking. The process node differs: 5 nm for the EPYC, 4 nm for the Ryzen, with the Ryzen packing more transistors (16,630 million versus 13,140 million) on a slightly smaller die (2x 70.6 mm² versus 2x 71 mm²).

Memory bandwidth favors the Ryzen at 89.6 GB/s versus 83.2 GB/s, despite both using dual-channel DDR5. L1 cache is larger on the Ryzen at 80 KB per core versus 64 KB per core, while L2 and L3 caches are identical at 1 MB per core and 64 MB shared, respectively. Integrated graphics differ: the EPYC has Radeon Graphics, while the Ryzen has the Radeon 610M. The EPYC’s launch MSRP is $699, and it was released on 2024-05-20, while the Ryzen was released on 2025-01-05 with no listed MSRP. Both support ECC memory and offer PCIe Gen 5 with 28 lanes, but the EPYC targets the server/workstation segment, while the Ryzen is a mobile part.