AMD EPYC 8324P vs AMD Ryzen 9 9955HX Comparison

Architecture Differences

The AMD EPYC 8324P and AMD Ryzen 9 9955HX represent two fundamentally different design philosophies from AMD, targeting entirely separate market segments. The EPYC 8324P is a server/workstation processor built on the Zen 4c architecture, codenamed Siena, while the Ryzen 9 9955HX is a mobile part using the newer Zen 5 architecture, codenamed Fire Range.

The most striking architectural difference lies in core configuration. The EPYC 8324P packs 32 cores and 64 threads, double the Ryzen 9 9955HX's 16 cores and 32 threads. This core advantage comes from the Zen 4c design, which prioritizes density and power efficiency per core. The Ryzen 9 9955HX counters with a significantly higher boost clock of 5.40 GHz versus the EPYC's 3.00 GHz, though its base clock of 2.50 GHz is slightly lower than the EPYC's 2.65 GHz.

Process technology also differs. The EPYC 8324P uses TSMC's 5 nm process with 35,500 million transistors across a 4x 73 mm² die configuration. The Ryzen 9 9955HX moves to a more advanced 4 nm node with 16,630 million transistors on a 2x 70.6 mm² layout. Despite the smaller node, the Ryzen's transistor count is less than half the EPYC's, reflecting the core count disparity.

Cache hierarchy diverges significantly. The EPYC 8324P provides 64 KB of L1 per core, 1 MB of L2 per core, and a massive 128 MB of shared L3 cache. The Ryzen 9 9955HX has 80 KB of L1 per core, also 1 MB of L2 per core, but only 64 MB of shared L3 cache, half of the EPYC's allocation. This gives the server chip a substantial capacity advantage for workloads that benefit from large working sets.

Memory architecture further separates the two. The EPYC 8324P supports six-channel DDR5 memory with a peak bandwidth of 230.4 GB/s, while the Ryzen 9 9955HX uses dual-channel DDR5 with 89.6 GB/s. Both support ECC memory. PCIe Gen 5 is present on both, but the EPYC provides 96 CPU lanes versus the Ryzen's 28, a massive difference in expansion capability.

Thermal design points tell the story of intended use. The EPYC 8324P has a TDP of 180 W, while the Ryzen 9 9955HX is rated at just 55 W. The EPYC also uses socket SP6, while the Ryzen uses socket FL1. The Ryzen includes Radeon 610M integrated graphics, whereas the EPYC has no integrated graphics. The Ryzen 9 9955HX has an unlocked multiplier, while the EPYC is locked. Release dates differ as well: the EPYC launched in September 2023, the Ryzen in January 2025.

FAQ

Q: Which processor has more cores and threads?

A: The AMD EPYC 8324P has 32 cores and 64 threads, which is exactly double the Ryzen 9 9955HX's 16 cores and 32 threads.

Q: How does the boost clock compare between the two chips?

A: The Ryzen 9 9955HX reaches a boost clock of 5.40 GHz, far higher than the EPYC 8324P's maximum of 3.00 GHz. The base clocks are closer: 2.50 GHz for the Ryzen versus 2.65 GHz for the EPYC.

Q: Which processor has more L3 cache?

A: The EPYC 8324P features 128 MB of shared L3 cache, while the Ryzen 9 9955HX has 64 MB. The EPYC offers double the L3 capacity.

Q: What is the memory bandwidth difference?

A: The EPYC 8324P supports six-channel DDR5 memory with 230.4 GB/s of bandwidth. The Ryzen 9 9955HX uses dual-channel memory, providing 89.6 GB/s, which is significantly lower.

Q: Which processor has integrated graphics?

A: Only the Ryzen 9 9955HX includes integrated graphics, in the form of a Radeon 610M. The EPYC 8324P has no integrated graphics unit.

Q: What are the thermal design power ratings?

A: The EPYC 8324P has a TDP of 180 W, whereas the Ryzen 9 9955HX is rated for 55 W, reflecting the server versus mobile design goals.

Head-to-Head Benchmarks

The recorded benchmark data shows a clear overall winner in the EPYC 8324P, which secures 12 wins out of 15 head-to-head comparisons. The Ryzen 9 9955HX takes only 3 wins, but those wins are notable for specific workloads.

The largest single-core victory belongs to the EPYC 8324P in Cinebench R23 single-core, where it scores 6855 against the Ryzen's 2174, a 215.3% advantage. The Cinebench R15 single-core test shows a similar pattern: the EPYC scores 690 versus 336, a 105.4% delta. These results are surprising given the Ryzen's much higher boost clock, indicating the EPYC's architecture handles the single-threaded workload differently in this test.

Multicore performance is decisive for the EPYC. In Cinebench R23 multicore, it scores 48557 versus 37159, a 30.7% lead. The Cinebench R15 multicore test goes the other way, with the Ryzen scoring 5905 against the EPYC's 4894, a 17.1% margin. This inconsistency highlights the differences in scaling behavior between the two architectures.

PassMark results show the EPYC dominating nearly every category. Data compression sees the EPYC at 980907 versus 731998, a 34% advantage. Data encryption shows a 69.3% lead, with scores of 63195 and 37330. Physics testing reveals a 70.5% delta, 4637 versus 2720. Random string sorting shows the EPYC ahead by 45.9%, while integer math has it 16.9% ahead at 248447 versus 212598.

The Ryzen 9 9955HX's wins are concentrated in specific areas. PassMark single-thread (and singlethread) scores show the Ryzen at 4393 versus the EPYC's 2367, a 46.1% advantage. The Cinebench R15 multicore win is 17.1% as noted. The Ryzen is also close in several other tests, such as PassMark floating point math (136682 versus 139022, a 1.7% EPYC lead) and PassMark multithread (57127 versus 56171, also a 1.7% EPYC lead). Extended instructions see the EPYC winning by only 4.1%.

Specification Differences

The two processors differ across nearly every specification category. The EPYC 8324P offers 32 cores and 64 threads, while the Ryzen 9 9955HX provides 16 cores and 32 threads. Clock speeds diverge: the EPYC has a 2.65 GHz base and 3.00 GHz boost, while the Ryzen has a 2.50 GHz base and 5.40 GHz boost. TDP is 180 W for the EPYC and 55 W for the Ryzen.

Memory support differs in channel count and bandwidth. The EPYC uses six-channel DDR5 with 230.4 GB/s, the Ryzen uses dual-channel DDR5 with 89.6 GB/s. Both support ECC memory. PCIe Gen 5 lanes are 96 for the EPYC and 28 for the Ryzen. The socket is SP6 for the EPYC and FL1 for the Ryzen.

Cache allocations vary: L1 is 64 KB per core for the EPYC and 80 KB per core for the Ryzen. L2 is 1 MB per core for both. L3 is 128 MB shared for the EPYC and 64 MB shared for the Ryzen. The EPYC lacks integrated graphics, while the Ryzen includes Radeon 610M.

Architecture and process node differ. The EPYC uses Zen 4c on 5 nm with 35,500 million transistors and a 4x 73 mm² die. The Ryzen uses Zen 5 on 4 nm with 16,630 million transistors and a 2x 70.6 mm² die. The EPYC is in the EPYC 8004 series, the Ryzen is in the 9000 series.

The EPYC is a server/workstation part with a launch MSRP of $1895, while the Ryzen is a mobile processor with no launch MSRP recorded. The EPYC has a locked multiplier, the Ryzen is unlocked. Release dates are September 2023 for the EPYC and January 2025 for the Ryzen.

The Verdict

The data points in favor of the EPYC 8324P for most compute-heavy tasks. Its 12 wins out of 15 benchmark comparisons, including a 30.7% lead in Cinebench R23 multicore and a 69.3% advantage in data encryption, make it the stronger choice for parallel workloads where a 32-core, 64-thread configuration can be fully utilized. The 128 MB L3 cache and 230.4 GB/s memory bandwidth support large datasets and high-throughput server applications.

The Ryzen 9 9955HX is the better option for single-threaded performance, where it records a 46.1% advantage over the EPYC in PassMark single-thread. Its 5.40 GHz boost clock likely explains this edge. It also wins in Cinebench R15 multicore, but that is an outlier against the EPYC's larger multicore lead in the more modern R23 test.

Those who need maximum core count, cache capacity, memory bandwidth, and PCIe lanes should choose the EPYC 8324P. The 180 W TDP and server socket are the trade-offs. The Ryzen 9 9955HX suits scenarios where low power consumption (55 W), integrated graphics, and unlocked multiplier matter, such as a compact workstation or mobile workstation. Its 16 cores still provide solid performance, but the benchmark record shows the EPYC ahead in most categories. The choice comes down to whether raw throughput and expansion capability, or single-core speed and power efficiency, are the priority.