AMD EPYC 9655 vs AMD EPYC 9755 Comparison

The AMD EPYC 9755 and AMD EPYC 9655 are both Zen 5 Turin parts on the same SP5 platform, but the benchmark data draws a clear line between them. The 9755 is the undisputed throughput champion, winning 15 of 17 head-to-head tests, while the 9655 counters with a decisive single-thread advantage. The choice is not about which is "better" but which workload profile you prioritize: raw parallel compute versus per-core responsiveness.

Where Each One Wins

The AMD EPYC 9755 dominates every multi-threaded and data-intensive workload in the comparison. Its 128 cores and 256 threads provide the foundation for wins across Cinebench R15, R20, and R23 multi-core tests, plus all PassMark compute categories that scale with core count. The 9755’s largest margins come in extended instructions (49.2% ahead), floating-point math (39.2% ahead), and data compression (38.1% ahead) — workloads that leverage both core quantity and the larger 512 MB L3 cache. For database, scientific computing, or virtualization environments where thread-level parallelism is the bottleneck, the 9755 is the clear pick.

The AMD EPYC 9655 wins exactly two tests, but they are meaningful: PassMark single-thread (3847 vs 3503) and the duplicate singlethread result, an 8.9% advantage. This stems from its higher boost clock of 4.50 GHz versus the 9755’s 4.10 GHz. The 9655 also carries a lower 400 W TDP and a smaller 384 MB L3 cache, making it a fit for workloads that are latency-sensitive or lightly threaded, where core count matters less than per-core speed. It is also the more efficient choice on paper for racks with power limits, though the data does not quantify that efficiency directly.

FAQ

Q: Which CPU has more cores?

A: The AMD EPYC 9755 has 128 cores and 256 threads, while the AMD EPYC 9655 has 96 cores and 192 threads.

Q: Is the AMD EPYC 9655 faster in any benchmark?

A: Yes. The 9655 wins the PassMark single-thread test with a score of 3847, compared to the 9755’s 3503, an 8.9% advantage. It also wins the duplicate singlethread test by the same margin.

Q: How much faster is the 9755 in multi-core rendering?

A: In Cinebench R23 multi-core, the 9755 scores 141378 against the 9655’s 132672, a 6.6% lead. The same 6.6% delta appears across all Cinebench R15, R20, and R23 tests, both single and multi-core.

Q: What is the largest performance gap between the two?

A: The largest gap is in PassMark extended instructions, where the 9755 scores 303321 versus the 9655’s 203285, a 49.2% difference. Data compression follows at 38.1% (4517407 vs 3271896).

Q: Do both CPUs support the same memory and PCIe?

A: Yes. Both support DDR5 with a twelve-channel memory bus and 576.0 GB/s bandwidth, and both provide PCIe Gen 5 with 128 lanes (CPU only). They also share the same AMD Socket SP5.

Q: What is the difference in single-thread Cinebench scores?

A: In Cinebench R23 single-core, the 9755 scores 19959 and the 9655 scores 18730, giving the 9755 a 6.6% win. This contrasts with the PassMark single-thread result, where the 9655 leads by 8.9%.

Head-to-Head Benchmarks

The Cinebench suite shows a consistent pattern: the 9755 wins every test by exactly 6.6%. In Cinebench R15 multi-core, the 9755 posts 14250 against 13373; in R15 single-core, 2011 against 1887. R20 multi-core sees 59378 versus 55722, and R20 single-core sees 8382 versus 7866. R23 multi-core is 141378 versus 132672, and R23 single-core is 19959 versus 18730. The uniform delta suggests the 9755’s additional 32 cores provide a steady throughput edge that also carries over to its per-core Cinebench performance, despite the 9655’s higher boost clock.

The PassMark suite reveals where the two diverge sharply. The 9755 wins data compression 4517407 to 3271896 (38.1%), data encryption 284927 to 210555 (35.3%), extended instructions 303321 to 203285 (49.2%), find prime numbers 2047 to 1598 (28.1%), floating-point math 922900 to 662958 (39.2%), and integer math 1549946 to 1139161 (36.1%). These are not marginal wins; they are substantial gaps that reflect the 9755’s core-count advantage in highly parallel arithmetic and memory-intensive operations. Random string sorting also favors the 9755 by 29.9% (571185 vs 439682).

The only reversal occurs in PassMark single-thread, where the 9655 scores 3847 versus the 9755’s 3503, an 8.9% edge. That single result is the 9655’s entire counterargument. The 9755 still wins PassMark multithread by 6.5% (166328 vs 156110) and physics by 7.2% (27806 vs 25947), but those margins are far narrower than the compute-heavy PassMark tests, indicating that the 9655’s higher clock speed narrows the gap in tasks that do not perfectly scale with core count.

Specification Differences

The core and thread counts are the primary differentiators: 128 cores and 256 threads on the 9755 versus 96 cores and 192 threads on the 9655. The 9755 has a higher base clock at 2.70 GHz versus 2.60 GHz, but the 9655 has a higher boost clock at 4.50 GHz versus 4.10 GHz. TDP differs significantly: 500 W for the 9755 versus 400 W for the 9655. The 9755 packs 133,040 million transistors across 16x 70.6 mm² dies, while the 9655 uses 99,780 million transistors on 12x 70.6 mm² dies. L3 cache is 512 MB shared on the 9755 versus 384 MB shared on the 9655. Both share the same L1 (80 KB per core) and L2 (1 MB per core) cache structure, and both carry a launch MSRP: $12984 for the 9755 and $11852 for the 9655.

Architecture Differences

Both CPUs are built on the same Zen 5 architecture with the Turin codename, fabricated on TSMC’s 4 nm process. The foundry and process node are identical, as are the socket (AMD Socket SP5), memory support (DDR5, twelve-channel, 576.0 GB/s), and PCIe configuration (Gen 5, 128 lanes CPU only). The architectural divergence is purely a matter of silicon scale and clock tuning. The 9755 uses 16 compute dies versus the 9655’s 12, which explains its higher transistor count (133,040 million vs 99,780 million) and larger shared L3 (512 MB vs 384 MB). The 9655 compensates for fewer dies with a 0.40 GHz higher boost clock, which directly explains its PassMark single-thread win. Both are active production parts with ECC memory support and no integrated graphics, and both were released on the same date. The 9755’s higher TDP (500 W vs 400 W) reflects the cost of powering 32 additional cores and 128 MB more L3 cache.

The Verdict

The data is unambiguous for scale-out workloads: the AMD EPYC 9755 is the superior processor. It wins every Cinebench test and 13 of 15 PassMark tests, with margins ranging from 6.5% in multithread to 49.2% in extended instructions. Its 128 cores, 512 MB L3 cache, and higher base clock deliver a consistent throughput advantage that no benchmark in this comparison contradicts. For HPC, large-scale virtualization, or heavy batch processing, the 9755 is the only rational choice from these two.

The AMD EPYC 9655 earns its place through the PassMark single-thread result (3847 vs 3503) and its 4.50 GHz boost clock. It also offers a lower 400 W TDP and 128 MB less L3 cache, which could ease power and thermal management in dense server chassis. For users running latency-sensitive applications, database transaction processing, or any workload where per-core speed matters more than aggregate core count, the 9655’s 8.9% single-thread edge is a tangible advantage. It is also the stronger pick if the workload rarely exceeds 96 threads, since the 9755’s extra cores would sit idle. The verdict: choose the 9755 for maximum parallel throughput, choose the 9655 for single-thread responsiveness and lower power draw. The 9755 is the overall benchmark leader by average score (505778 vs 373479), but the 9655 is not a compromise — it is a specialized tool for a different job.