AMD EPYC 9255 vs AMD EPYC 9384X Comparison

The AMD EPYC 9384X and AMD EPYC 9255 represent two distinct approaches to server performance within the same socket ecosystem. The 9384X is a 32-core Zen 4 part built on the 5 nm node with a massive 768 MB of shared L3 cache, while the 9255 is a 24-core Zen 5 part on the 4 nm node with a much smaller 128 MB L3 cache but significantly higher clock speeds. The benchmark data shows a clear split: the 9255 wins the majority of tests, but the 9384X holds decisive victories in specific workloads that leverage its cache advantage. This analysis breaks down exactly where each processor excels and which workloads favor which design.

Head-to-Head Benchmarks

The most striking result is in single-threaded performance. The EPYC 9255 scores 3,655 in PassMark single-thread, which is 17.5% higher than the 9384X’s 3,015. This gap is consistent across all Cinebench single-core tests: the 9255 leads by 8% in R15 (915 vs 842), 7.9% in R20 (3,813 vs 3,510), and 7.9% in R23 (9,080 vs 8,359). The 9255’s 4.80 GHz boost clock versus the 9384X’s 3.90 GHz is the primary driver here, and the newer Zen 5 architecture compounds that advantage.

Multi-core results also favor the 9255, despite the 9384X having 8 more cores. In Cinebench R23 multi-core, the 9255 scores 64,318 versus 59,215, a 7.9% lead. The same 7.9% delta appears in R20 multi-core (27,013 vs 24,870) and R15 multi-core (6,483 vs 5,968). PassMark multithread shows a 9% lead for the 9255 (76,580 vs 69,665). This is a remarkable outcome — the 24-core part beats the 32-core part in heavily threaded rendering workloads, thanks to higher per-core efficiency and clock speed.

However, the 9384X dominates in data-intensive tasks. PassMark data encryption shows the 9384X at 72,631 versus 59,668, a massive 21.7% advantage. Data compression also goes to the 9384X: 1,119,983 versus 1,018,904, a 9.9% lead. Find prime numbers is a narrow 2.8% win for the 9384X (596 vs 580). These three wins suggest the 768 MB L3 cache provides a substantial benefit for workloads that repeatedly access large datasets.

The remaining tests are closer. Floating point math favors the 9255 by 4.8% (183,367 vs 174,630), integer math favors it by 2.8% (306,442 vs 297,833), and physics by 4.2% (9,740 vs 9,332). Extended instructions are nearly tied, with the 9255 ahead by just 1.1% (75,185 vs 74,363). Random string sorting goes to the 9255 by 7.6% (129,202 vs 119,440). Overall, the 9255 wins 14 out of 17 head-to-head tests, but the 9384X’s wins are in categories where its margin is particularly large.

FAQ

Q: Which CPU has the higher average benchmark score?

A: The AMD EPYC 9384X has a slightly higher average benchmark score of 120,427 compared to the 9255’s 116,388. The 9384X sits 3.5% above the 9255 in its nearestRivals data, while the 9255 is 3.4% below the 9384X in its own listing.

Q: Why does the 9255 win so many tests despite having fewer cores?

A: The 9255 has a 4.80 GHz boost clock versus 3.90 GHz for the 9384X, and it uses the newer Zen 5 architecture on a 4 nm process. These factors allow the 24-core part to outperform the 32-core part in multi-core Cinebench tests by 7.9%, as the higher per-core throughput overcomes the core count deficit.

Q: Where does the 9384X show its biggest advantage?

A: The 9384X’s largest win is in PassMark data encryption, where it scores 72,631 versus 59,668 — a 21.7% margin. It also leads by 9.9% in data compression. These are cache-sensitive workloads where the 768 MB L3 cache provides a decisive edge.

Q: How do the two compare in single-threaded performance?

A: The 9255 is clearly ahead, scoring 3,655 in PassMark single-thread versus 3,015 for the 9384X, a 17.5% difference. Cinebench single-core tests show consistent 7.9-8% leads for the 9255 across R15, R20, and R23.

Q: What is the memory bandwidth difference?

A: The 9255 offers 576.0 GB/s of memory bandwidth, while the 9384X provides 460.8 GB/s. Both use twelve-channel DDR5 memory, but the 9255’s higher bandwidth contributes to its wins in memory-intensive benchmarks like random string sorting.

Q: Are both CPUs on the same socket?

A: Yes, both use AMD Socket SP5 and support PCIe Gen 5 with 128 lanes (CPU only). They also both support ECC memory, making them drop-in compatible for systems designed for this platform.

Architecture Differences

The two processors come from different generations of AMD’s EPYC lineup. The 9384X is part of the EPYC 9004 series, built on the Zen 4 architecture with the codename Genoa-X. It uses a 5 nm process from TSMC and packs 90,160 million transistors across 8 dies, each measuring 72 mm². The 9255 belongs to the EPYC 9005 series, using the Zen 5 architecture with the codename Turin. It is manufactured on a 4 nm process and contains 33,260 million transistors spread across 4 dies of 70.6 mm² each.

The most dramatic architectural difference is in cache. The 9384X features 768 MB of shared L3 cache — this is the "X" variant with 3D V-Cache technology. The 9255 has only 128 MB of shared L3 cache. Per-core L1 cache also differs: the 9384X has 64 KB per core, while the 9255 has 80 KB per core. Both have 1 MB of L2 cache per core. The larger L3 on the 9384X is clearly aimed at workloads where data locality matters, while the 9255’s smaller cache is compensated by higher clock speeds and a newer core design.

The 9255’s boost clock of 4.80 GHz is substantially higher than the 9384X’s 3.90 GHz, and its base clock of 3.25 GHz also exceeds the 9384X’s 3.10 GHz. The 9255 achieves this with a lower TDP of 200 watts versus 320 watts for the 9384X. Both use TSMC as the foundry, but the process node difference (4 nm vs 5 nm) explains some of the efficiency gains.

Specification Differences

The core count is the most obvious difference: the 9384X has 32 cores and 64 threads, while the 9255 has 24 cores and 48 threads. Clock speeds favor the 9255, with a 3.25 GHz base and 4.80 GHz boost versus 3.10 GHz base and 3.90 GHz boost on the 9384X. TDP is 320 watts for the 9384X and 200 watts for the 9255, a significant power envelope difference.

Cache configuration is starkly different. The 9384X has 64 KB of L1 per core and 768 MB of shared L3, while the 9255 has 80 KB of L1 per core and 128 MB of shared L3. Both share 1 MB of L2 per core. Memory bandwidth favors the 9255 at 576.0 GB/s versus 460.8 GB/s, despite both using twelve-channel DDR5.

The 9384X was released on 2023-06-12 with a launch MSRP of $5529. The 9255 came later, on 2024-10-09, with a launch MSRP of $2495. Both are active in production and neither has an unlocked multiplier. The 9255 has a part number of 100-000000694, while the 9384X does not list one. The 9255 lists integrated graphics as "N/A," while the 9384X does not specify. Both support ECC memory and use the same AMD Socket SP5.

The Verdict

The data presents a clear choice based on workload type. The EPYC 9255 is the better all-around performer, winning 14 of 17 head-to-head benchmarks. It leads in every Cinebench test, all single-threaded workloads, and most PassMark math and sorting tests. Its 17.5% lead in single-thread performance and 7.9% lead in multi-core Cinebench make it the superior choice for general server workloads, rendering, and any application that benefits from higher clock speeds. The 9255 also consumes 120 watts less power (200 vs 320) and offers higher memory bandwidth.

The EPYC 9384X is the specialist. Its 21.7% lead in data encryption and 9.9% lead in data compression are not trivial — these are common enterprise workloads. The 768 MB L3 cache is a massive resource for databases, in-memory analytics, and other cache-resident workloads. For users running these specific applications, the 9384X’s wins are more valuable than the 9255’s broader but smaller margins.

Neither CPU is a bad choice, but the 9255 is the more versatile option. The 9384X is a niche product that trades general performance for extreme cache capacity. If your workloads fit in that cache, the 9384X is worth the premium; if not, the 9255’s higher clock speeds and newer architecture make it the data-driven pick.

Where Each One Wins

AMD EPYC 9384X wins in:

• Data encryption: 72,631 vs 59,668 (21.7% lead)
• Data compression: 1,119,983 vs 1,018,904 (9.9% lead)
• Prime number finding: 596 vs 580 (2.8% lead)
• Scenarios involving large, repeated data access where the 768 MB L3 cache can hold working sets entirely on-die

AMD EPYC 9255 wins in:

• All Cinebench tests: R15, R20, R23 multi-core and single-core, with consistent 7.9-8% leads
• PassMark single-thread: 3,655 vs 3,015 (17.5% lead)
• PassMark multithread: 76,580 vs 69,665 (9% lead)
• Floating point math: 183,367 vs 174,630 (4.8% lead)
• Integer math: 306,442 vs 297,833 (2.8% lead)
• Physics: 9,740 vs 9,332 (4.2% lead)
• Random string sorting: 129,202 vs 119,440 (7.6% lead)
• Extended instructions: 75,185 vs 74,363 (1.1% lead)
• General-purpose server workloads, high-frequency trading, web serving, and any task where clock speed matters more than cache size