AMD EPYC 9354 vs AMD Ryzen 9 PRO 9955 Comparison

The AMD EPYC 9354 and AMD Ryzen 9 PRO 9955 represent two distinct approaches to high-end x86 computing, one optimized for massive parallel throughput in a server socket and the other for high-frequency responsiveness in a workstation platform. The benchmark data reveals a stark division of labor: the EPYC 9354 dominates nearly every multithreaded and specialized workload, while the Ryzen 9 PRO 9955 counters with a decisive victory in single-thread performance. This analysis walks through the recorded measurements, architectural foundations, and practical implications of each processor's design.

Head-to-Head Benchmarks

The head-to-head results are overwhelmingly one-sided in terms of raw throughput. The EPYC 9354 wins 9 of the 11 recorded comparisons, with margins that range from substantial to massive. In PassMark's multithread test, the EPYC 9354 scores 72,615 against the Ryzen 9 PRO 9955's 54,866, a 32.3% advantage. This gap widens considerably in more specialized workloads. The data encryption test shows the EPYC 9354 at 71,400 versus 33,754, giving it a 111.5% lead, more than double the Ryzen's output. Similarly, the find prime numbers test records 934 for the EPYC 9354 against 461 for the Ryzen 9 PRO 9955, a 102.6% difference.

The pattern continues across other compute-intensive benchmarks. Data compression favors the EPYC 9354 at 1,168,626 versus 684,470, a 70.7% margin. Integer math shows 304,828 against 182,312, a 67.2% advantage. Extended instructions score 86,176 for the EPYC 9354 versus 54,903 for the Ryzen 9 PRO 9955, a 57% lead. Floating point math records 188,894 versus 121,509, a 55.5% difference. Random string sorting shows 140,690 against 71,928, a 95.6% gap. The largest discrepancy appears in the physics test, where the EPYC 9354 scores 9,281 versus the Ryzen's 3,332, an extraordinary 178.5% advantage.

The single exception to this dominance is the single-thread test. Here the Ryzen 9 PRO 9955 scores 4,597, while the EPYC 9354 manages 2,601. That is a 43.4% deficit for the EPYC part, and it is the only benchmark category where the Ryzen 9 PRO 9955 comes out ahead. The result appears twice in the data, once as passmark_single_thread and once as passmark_singlethread, with identical scores, confirming the consistency of the measurement. For workloads that depend on a single core's clock speed, the Ryzen 9 PRO 9955 is clearly the stronger choice, but for everything else, the EPYC 9354's core count and cache capacity carry the day.

Architecture Differences

The two processors are built on different generations of AMD's core designs. The EPYC 9354 uses the Zen 4 architecture, codenamed Genoa, part of the EPYC 9004 series. The Ryzen 9 PRO 9955 uses the Zen 5 architecture, codenamed Granite Ridge, from the 9000 series. The process nodes also differ, with the EPYC 9354 fabricated on a 5 nm process and the Ryzen 9 PRO 9955 on a 4 nm process, both from TSMC. The transistor counts reflect the scale difference: the EPYC 9354 packs 52,560 million transistors across eight 72 mm² dies, while the Ryzen 9 PRO 9955 uses 16,630 million transistors on two 70.6 mm² dies.

Core and thread counts diverge sharply. The EPYC 9354 offers 32 cores and 64 threads, while the Ryzen 9 PRO 9955 provides 12 cores and 24 threads. This 20-core gap is the primary driver of the EPYC's multithreaded victories. Clock speeds tell the opposite story. The EPYC 9354 has a base clock of 3.25 GHz and a boost clock of 3.80 GHz. The Ryzen 9 PRO 9955 starts at 3.40 GHz base but boosts to 5.40 GHz, a 1.60 GHz advantage at peak that explains its single-thread superiority.

Cache hierarchies also differ substantially. The EPYC 9354 allocates 64 KB of L1 cache per core and 1 MB of L2 per core, with a massive 256 MB of shared L3 cache. The Ryzen 9 PRO 9955 provides 80 KB of L1 per core, 1 MB of L2 per core, and 64 MB of L3 cache. The EPYC's L3 cache is four times larger, which benefits server workloads with large working sets. The Ryzen's larger per-core L1 may help with certain latency-sensitive tasks.

Memory subsystems follow the platform divide. Both support DDR5 and ECC memory, but the EPYC 9354 uses a twelve-channel memory bus with a bandwidth of 460.8 GB/s. The Ryzen 9 PRO 9955 uses a dual-channel bus with 89.6 GB/s. The EPYC's memory bandwidth is more than five times higher, a critical factor for data-intensive applications. PCIe connectivity also differs, with the EPYC 9354 offering 128 Gen 5 lanes (CPU only) versus 24 Gen 5 lanes for the Ryzen 9 PRO 9955. The Ryzen 9 PRO 9955 includes integrated Radeon Graphics, while the EPYC 9354 has no integrated graphics. The sockets are incompatible: the EPYC 9354 uses AMD Socket SP5, and the Ryzen 9 PRO 9955 uses AMD Socket AM5.

Where Each One Wins

The EPYC 9354 is built for parallel throughput. Its 32 cores and 64 threads, combined with 256 MB of L3 cache and twelve-channel memory, make it the clear winner in any workload that can scale across multiple threads. The data shows this in every multithreaded benchmark category. The physics test result, with a 178.5% lead, points to simulation and modeling workloads that heavily utilize many cores. Data encryption and compression, with leads of 111.5% and 70.7% respectively, indicate strong performance for database operations, file servers, and security applications. Integer math and floating point math, with 67.2% and 55.5% leads, cover general computational tasks in scientific computing, financial modeling, and rendering.

The Ryzen 9 PRO 9955 wins where single-thread performance matters. Its 5.40 GHz boost clock delivers a 43.4% advantage in the single-thread benchmark, making it the better choice for legacy applications that rely on one or two cores, interactive workloads, and tasks where latency per operation is more important than aggregate throughput. The larger 80 KB L1 cache per core may also contribute to its responsiveness in these scenarios. The Ryzen also has a lower TDP at 120 watts versus 280 watts, which could factor into system cooling and power delivery design, though the performance data does not directly measure efficiency.

FAQ

Q: Which processor has more cores and threads?

A: The AMD EPYC 9354 has 32 cores and 64 threads. The AMD Ryzen 9 PRO 9955 has 12 cores and 24 threads.

Q: How much faster is the EPYC 9354 in multithreaded workloads?

A: In the PassMark multithread test, the EPYC 9354 scores 72,615 versus 54,866 for the Ryzen 9 PRO 9955, a 32.3% advantage. The margin is larger in specialized tests, such as physics, where the EPYC leads by 178.5%.

Q: Which processor has higher clock speeds?

A: The Ryzen 9 PRO 9955 has a base clock of 3.40 GHz and a boost clock of 5.40 GHz. The EPYC 9354 has a base clock of 3.25 GHz and a boost clock of 3.80 GHz.

Q: How do the cache sizes compare?

A: The EPYC 9354 has 64 KB of L1 cache per core, 1 MB of L2 cache per core, and 256 MB of shared L3 cache. The Ryzen 9 PRO 9955 has 80 KB of L1 cache per core, 1 MB of L2 cache per core, and 64 MB of L3 cache.

Q: What memory bandwidth does each processor support?

A: The EPYC 9354 supports a twelve-channel DDR5 memory bus with 460.8 GB/s bandwidth. The Ryzen 9 PRO 9955 supports a dual-channel DDR5 bus with 89.6 GB/s bandwidth.

Q: Which processor has integrated graphics?

A: The Ryzen 9 PRO 9955 includes Radeon Graphics. The EPYC 9354 has no integrated graphics.

Specification Differences

The EPYC 9354 and Ryzen 9 PRO 9955 differ across nearly every specification category. The EPYC 9354 uses 32 cores and 64 threads, while the Ryzen 9 PRO 9955 uses 12 cores and 24 threads. The EPYC has a base clock of 3.25 GHz and a boost clock of 3.80 GHz; the Ryzen has a base clock of 3.40 GHz and a boost clock of 5.40 GHz. TDP is 280 watts for the EPYC and 120 watts for the Ryzen. The EPYC uses AMD Socket SP5, while the Ryzen uses AMD Socket AM5. The architecture is Zen 4 (Genoa) for the EPYC and Zen 5 (Granite Ridge) for the Ryzen. Process nodes are 5 nm and 4 nm, respectively. Transistors number 52,560 million for the EPYC across eight 72 mm² dies, versus 16,630 million for the Ryzen across two 70.6 mm² dies.

Cache configurations differ in L1 and L3. The EPYC offers 64 KB of L1 per core and 256 MB of shared L3, while the Ryzen offers 80 KB of L1 per core and 64 MB of L3. Both have 1 MB of L2 per core. Memory bus width is twelve-channel for the EPYC and dual-channel for the Ryzen, with bandwidths of 460.8 GB/s and 89.6 GB/s. PCIe lanes are 128 Gen 5 for the EPYC and 24 Gen 5 for the Ryzen. The Ryzen includes Radeon Graphics; the EPYC does not. The EPYC has a launch MSRP of $3420, while the Ryzen has no recorded launch MSRP. The EPYC was released on 2022-11-09, and the Ryzen on 2026-06-29.

The Verdict

The choice between these two processors depends entirely on workload characteristics. For server and workstation environments where multithreaded throughput is the priority, the EPYC 9354 is the clear pick. Its 32 cores, 64 threads, 256 MB of L3 cache, and twelve-channel memory bandwidth deliver decisive wins in every parallel benchmark category, from 32.3% in multithread to 178.5% in physics. The data also shows it edges out its nearest rivals, with an average benchmark score of 126,810 against 124,756 for the Intel Xeon 6730P, a 1.6% delta, and 129,930 for the Intel Xeon 6710E, a -2.4% delta, placing it in the 97th percentile of all CPUs.

For users whose workloads are dominated by single-thread performance, the Ryzen 9 PRO 9955 is the better option. Its 5.40 GHz boost clock provides a 43.4% single-thread advantage over the EPYC 9354, and its average benchmark score of 110,612 places it in the same 97th percentile. Its nearest rival, the Intel Xeon w7-2595X, scores 108,663, a 1.8% delta, while the Intel Xeon 6527P scores 115,190, a -4% delta. The Ryzen also offers integrated graphics and a lower TDP of 120 watts, making it more suitable for compact workstation builds, though its 12-core, 24-thread configuration and 64 MB L3 cache limit its appeal for heavily threaded server workloads. The verdict from the data is straightforward: the EPYC 9354 for parallel compute, the Ryzen 9 PRO 9955 for single-thread responsiveness.