AMD EPYC 9555P vs AMD EPYC 9684X Comparison

The Verdict

The AMD EPYC 9684X and AMD EPYC 9555P serve fundamentally different roles, and the benchmark data makes that split clear. The 9684X wins 6 of 17 head-to-head tests, while the 9555P takes 11. The 9555P is the better all-round compute processor, but the 9684X is the specialist for encryption, compression, and prime-number workloads. Choose the 9555P if you need maximum multithreaded throughput across Cinebench and general integer/floating-point math. Choose the 9684X if your workloads involve heavy data encryption, compression, or prime-number computation, where it beats a newer, faster-clocked chip by substantial margins. The 9684X also has a 99th percentile ranking among all CPUs, but so does the 9555P — both are top-tier parts.

Architecture Differences

The 9684X is built on TSMC's 5 nm process with Zen 4 architecture under the Genoa-X codename. It packs 96 cores and 192 threads, with a base clock of 2.55 GHz and a boost clock of 3.70 GHz. Its thermal envelope is 400 W TDP. The chip uses 135,240 million transistors across a die size of 12x 72 mm². Its L1 cache is 64 KB per core, L2 is 1 MB per core, and L3 is a massive 1152 MB shared. That L3 is the defining feature — it dwarfs the 9555P's 256 MB shared L3 by a factor of 4.5.

The 9555P is the newer part, released in October 2024 versus the 9684X's June 2023 launch. It uses TSMC's 4 nm process with Zen 5 architecture under the Turin codename. It has 64 cores and 128 threads — exactly two-thirds the core count of the 9684X. But it runs faster: 3.20 GHz base and 4.40 GHz boost, with a lower 360 W TDP. Transistor count is 66,520 million across 8x 70.6 mm² dies. L1 cache is larger per core at 80 KB, L2 stays at 1 MB per core, but L3 is far smaller at 256 MB shared.

Both chips use AMD Socket SP5, support DDR5 memory, have twelve-channel memory buses, and offer PCIe Gen 5 with 128 lanes (CPU only). Both support ECC memory. Neither has integrated graphics, and both are unlocked multipliers set to false. The 9555P's memory bandwidth is 576.0 GB/s versus 460.8 GB/s for the 9684X — a 25% advantage for the newer chip.

Where Each One Wins

The 9555P dominates in rendering and general compute. It wins every Cinebench test (R15, R20, R23) in both single-core and multi-core by exactly 10.3% across the board. That uniformity suggests a consistent per-core performance advantage rather than a scaling benefit. The 9555P also wins PassMark multithread by 10.3%, single-thread by 22.4%, extended instructions by 1.3%, and floating-point math by 1.7%. For database workloads, scientific simulation, or any rendering task, the 9555P is clearly ahead.

The 9684X wins in specific, cache-hungry or parallel-sensitive tasks. Its data encryption score of 178,453 beats the 9555P's 155,805 by 14.5%. Data compression edges ahead by 2.6% (2,698,807 vs 2,630,921). The most dramatic win is in prime number computation: 2,020 vs 1,156, a 74.7% advantage. Integer math goes to the 9684X by 2.8%, physics by 24%, and random string sorting by 7.2%. These wins point to workloads that exploit the 9684X's massive 1152 MB L3 cache and its 96-core parallelism.

Notably, the 9684X's average benchmark score is 266,914 versus the 9555P's 291,664. The 9555P's nearest rival data shows it is 2.2% ahead of the EPYC 9565 and 9.3% ahead of the 9684X. The 9684X, by contrast, is 9.3% behind the 9555P and 14.1% behind the EPYC 9734. The 9555P also sits closer to the top of its rival group — it is only 6.1% behind the EPYC 9734 and 7.1% behind the EPYC 9575F, whereas the 9684X trails those same parts by larger margins.

FAQ

Q: Which CPU is faster in Cinebench R23 multi-core?

A: The AMD EPYC 9555P scores 115,186 versus the 9684X's 103,355, a 10.3% advantage. The same 10.3% delta applies to every Cinebench test — R15, R20, and R23, single-core and multi-core.

Q: Does the 9684X ever beat the 9555P?

A: Yes, in 6 of 17 tests. The biggest win is in PassMark find prime numbers (74.7% ahead), followed by physics (24% ahead) and data encryption (14.5% ahead). It also wins data compression, integer math, and random string sorting.

Q: How do their core counts and clocks compare?

A: The 9684X has 96 cores and 192 threads with a 2.55 GHz base and 3.70 GHz boost. The 9555P has 64 cores and 128 threads with a 3.20 GHz base and 4.40 GHz boost. The 9555P runs at higher clocks on fewer cores.

Q: Which chip has more L3 cache?

A: The 9684X has 1152 MB shared L3, while the 9555P has 256 MB shared L3. The 9684X's cache is 4.5 times larger, which explains its wins in cache-sensitive workloads like prime number computation.

Q: What is the memory bandwidth difference?

A: The 9555P offers 576.0 GB/s versus 460.8 GB/s for the 9684X. Both use DDR5 with twelve-channel memory buses. The 9555P's bandwidth advantage contributes to its Cinebench wins.

Q: Which processor has a higher single-thread score?

A: The 9555P scores 3,726 in PassMark single-thread versus 2,891 for the 9684X, a 22.4% advantage. In Cinebench R23 single-core, the 9555P scores 16,261 versus 14,591.

Head-to-Head Benchmarks

The most striking pattern in the data is the uniform 10.3% delta across all six Cinebench tests. The 9555P wins Cinebench R15 multi-core with 11,610 versus 10,418, R15 single-core with 1,638 versus 1,470, R20 multi-core with 48,378 versus 43,409, R20 single-core with 6,829 versus 6,128, R23 multi-core with 115,186 versus 103,355, and R23 single-core with 16,261 versus 14,591. Every single delta is exactly -10.3% from the 9684X's perspective. That consistency implies the 9555P's per-core efficiency advantage carries directly through multi-threaded rendering workloads without any scaling penalty from its lower core count.

The 9555P also wins PassMark multithread by the same 10.3% margin: 135,513 versus 121,595. Its single-thread victory is much larger in percentage terms — 3,726 versus 2,891, a 22.4% gap. That is the largest win for the 9555P in any test. In floating-point math, the 9555P takes a narrow 1.7% win (480,435 vs 472,174), and in extended instructions it wins by 1.3% (180,317 vs 177,956).

The 9684X's wins are more dramatic in proportional terms. The prime number test is the standout: 2,020 versus 1,156, a 74.7% advantage. That is the single largest delta in the entire comparison. Physics follows with 24% (24,686 vs 19,907). Data encryption shows a 14.5% lead (178,453 vs 155,805). Random string sorting goes 7.2% to the 9684X (349,126 vs 325,662). Integer math is close at 2.8% (844,145 vs 821,218), and data compression is the tightest 9684X win at 2.6% (2,698,807 vs 2,630,921).

The wins split cleanly along architectural lines. The 9684X's 1152 MB L3 cache and 96 cores give it an edge in workloads that can keep massive working sets resident on-chip. Prime number sieving, encryption, and compression all benefit from that cache. The 9555P's Zen 5 architecture and higher clocks win everything that scales with raw execution speed or per-core efficiency. The average benchmark scores confirm the overall picture: the 9555P's 291,664 average is 9.3% higher than the 9684X's 266,914.

Specification Differences

The two processors differ in every major architectural specification. Core count: 96 for the 9684X versus 64 for the 9555P. Threads: 192 versus 128. Base clock: 2.55 GHz versus 3.20 GHz. Boost clock: 3.70 GHz versus 4.40 GHz. TDP: 400 W versus 360 W. Process node: 5 nm versus 4 nm, both from TSMC. Transistors: 135,240 million versus 66,520 million. Die size: 12x 72 mm² versus 8x 70.6 mm².

Cache hierarchies differ significantly. L1 cache is 64 KB per core on the 9684X versus 80 KB per core on the 9555P. L2 is identical at 1 MB per core. L3 is 1152 MB shared on the 9684X versus 256 MB shared on the 9555P. Memory bandwidth favors the 9555P at 576.0 GB/s versus 460.8 GB/s.

Architecture and codename differ: Zen 4 (Genoa-X) versus Zen 5 (Turin). Release dates are June 2023 for the 9684X and October 2024 for the 9555P. The 9684X's launch MSRP is $14756; the 9555P's launch MSRP is $7983. Part numbers are 100-100000892 for the 9684X and 100-000001523 for the 9555P. Both share the same socket (SP5), memory support (DDR5), memory bus (twelve-channel), ECC support (true), PCIe configuration (Gen 5, 128 lanes CPU only), integrated graphics (none), market segment (Server/Workstation), production status (Active), and multiplier unlock (false). Their percentile rankings are both 99.