AMD EPYC 9355P vs AMD Ryzen Threadripper PRO 9975WX Comparison

The Verdict

The AMD Ryzen Threadripper PRO 9975WX and AMD EPYC 9355P are both 32-core, 64-thread Zen 5 processors, but the benchmark database shows they are built for different jobs. The Threadripper PRO 9975WX wins 15 of the 17 head-to-head comparisons, often by double-digit margins. The EPYC 9355P wins only two tests, but those two wins are massive and point to a specific strength.

For workstation users running Cinebench, compression, encryption, floating-point math, integer math, or single-threaded workloads, the Threadripper PRO 9975WX is the clear choice. Its 13.2% lead across all six Cinebench R15, R20, and R23 tests, both multi-core and single-core, shows a consistent advantage that makes it the better all-around compute part. The 17.6% single-thread win in PassMark reinforces this: the Threadripper simply clocks higher and delivers more per core.

For server administrators running physics simulations or prime-number workloads, the EPYC 9355P is the answer. The PassMark physics score of 13515 against 7288 is a 46.1% swing in its favor, and the find-prime-numbers score of 1044 against 620 is a 40.6% swing. These are not marginal wins; they are workload-specific blowouts that suggest the EPYC's memory subsystem and cache layout matter more in certain compute patterns.

The launch MSRP for the Threadripper PRO 9975WX is $4099. The launch MSRP for the EPYC 9355P is $2998. That price gap alone tells the buyer which market each chip targets, but the data shows the Threadripper earns its premium in most measured workloads.

Architecture Differences

Both processors are built on TSMC's 4 nm process node and share the Zen 5 architecture, but the physical implementations differ substantially. The Threadripper PRO 9975WX, codenamed Shimada Peak, uses four chiplets of 70.6 mm² each, totaling 33,260 million transistors. The EPYC 9355P, codenamed Turin, uses eight chiplets of the same 70.6 mm² size, totaling 66,520 million transistors. The EPYC packs roughly twice the transistor count and twice the chiplet count into the same package technology.

The cache structures are a major differentiator. The Threadripper PRO 9975WX has 64 KB of L1 per core, 1 MB of L2 per core, and 128 MB of L3. The EPYC 9355P has 80 KB of L1 per core, 1 MB of L2 per core, and 256 MB of shared L3. The EPYC's larger L1 and double L3 capacity directly explain its wins in physics and prime-number tests, which are often cache-sensitive.

Memory support also diverges. The Threadripper PRO 9975WX uses an eight-channel DDR5 memory bus with 409.6 GB/s bandwidth. The EPYC 9355P uses a twelve-channel DDR5 bus with 576.0 GB/s bandwidth. The EPYC's 40% higher memory bandwidth, 576.0 GB/s versus 409.6 GB/s, is a structural advantage for server workloads that stream large data sets.

Clock speeds tell the opposite story. The Threadripper PRO 9975WX runs at 4.00 GHz base and 5.40 GHz boost. The EPYC 9355P runs at 3.55 GHz base and 4.40 GHz boost. The Threadripper's 1.0 GHz higher boost ceiling explains its consistent single-thread and multi-thread wins in Cinebench and PassMark math tests.

The EPYC 9355P has a locked multiplier, while the Threadripper PRO 9975WX is multiplier-unlocked. Both support ECC memory, both use PCIe Gen 5 with 128 lanes from the CPU, and neither has integrated graphics. The Threadripper uses AMD Socket sTR5, the EPYC uses AMD Socket SP5. The Threadripper PRO 9975WX was released on 2025-07-22, while the EPYC 9355P was released on 2024-10-09.

FAQ

Q: Which processor is faster in single-threaded workloads?

A: The AMD Ryzen Threadripper PRO 9975WX. It leads by 13.2% in Cinebench R15, R20, and R23 single-core tests, and by 17.6% in PassMark single-thread tests. Its 5.40 GHz boost clock versus 4.40 GHz on the EPYC 9355P is the primary factor.

Q: Why does the EPYC 9355P win the physics benchmark?

A: The EPYC 9355P scores 13515 in PassMark physics against 7288 for the Threadripper PRO 9975WX, a 46.1% advantage. The EPYC's 256 MB of shared L3 and 80 KB L1 per core, along with 576.0 GB/s memory bandwidth, likely benefit the physics calculation pattern.

Q: Do both processors support ECC memory?

A: Yes, both the AMD Ryzen Threadripper PRO 9975WX and the AMD EPYC 9355P have ECC memory support enabled, and both use DDR5 memory.

Q: How do the two chips compare on memory bandwidth?

A: The EPYC 9355P has a twelve-channel memory bus delivering 576.0 GB/s, while the Threadripper PRO 9975WX has an eight-channel bus delivering 409.6 GB/s. The EPYC offers 166.4 GB/s more bandwidth.

Q: Which processor has more L3 cache?

A: The AMD EPYC 9355P has 256 MB of shared L3, exactly double the 128 MB on the AMD Ryzen Threadripper PRO 9975WX.

Q: When was each processor released?

A: The AMD EPYC 9355P was released on 2024-10-09, and the AMD Ryzen Threadripper PRO 9975WX was released on 2025-07-22.

Specification Differences

| Specification | AMD Ryzen Threadripper PRO 9975WX | AMD EPYC 9355P |

|---|---|---|

| Series | 9000 series | EPYC 9005 series |

| Base clock | 4.00 GHz | 3.55 GHz |

| Boost clock | 5.40 GHz | 4.40 GHz |

| TDP | 350 W | 280 W |

| Socket | AMD Socket sTR5 | AMD Socket SP5 |

| Codename | Shimada Peak | Turin |

| Transistors | 33,260 million | 66,520 million |

| Die size | 4x 70.6 mm² | 8x 70.6 mm² |

| L1 cache | 64 KB (per core) | 80 KB (per core) |

| L3 cache | 128 MB | 256 MB (shared) |

| Memory bus | Eight-channel | Twelve-channel |

| Memory bandwidth | 409.6 GB/s | 576.0 GB/s |

| Multiplier | Unlocked | Locked |

| Launch MSRP | $4099 | $2998 |

| Release date | 2025-07-22 | 2024-10-09 |

The core count, thread count, L2 cache, process node, foundry, PCIe configuration, ECC support, integrated graphics, and market segment are identical across both parts.

Head-to-Head Benchmarks

The Cinebench suite is a clean sweep for the Threadripper PRO 9975WX. In Cinebench R15 multi-core, it scores 9430 against 8332, a 13.2% lead. The single-core R15 result is 1331 against 1176, also 13.2%. Moving to R20, the multi-core score is 39292 against 34719, and single-core is 5546 against 4901. In R23, the Threadripper posts 93553 multi-core and 13207 single-core, against 82666 and 11670 respectively. Every Cinebench delta is exactly 13.2%, which suggests the clock advantage scales uniformly across all rendering workloads.

PassMark tells a more varied story. The Threadripper PRO 9975WX wins data compression with 1644573 against 1429976, a 15% margin. Data encryption goes to the Threadripper at 85035 versus 80961, a narrower 5% win. The extended instructions test is the biggest Threadripper win: 137733 against 107622, a 28% advantage. Floating-point math favors the Threadripper at 304833 versus 256635, an 18.8% margin. Integer math goes 461724 to 412067, a 12.1% win. Multi-thread performance is closer: 104902 versus 96603, an 8.6% edge. Random string sorting goes to the Threadripper at 188014 versus 176697, a 6.4% win.

The EPYC 9355P takes its only two wins in PassMark physics and prime-number finding. The physics score of 13515 against 7288 is a 46.1% swing in favor of the EPYC, the largest delta in the entire comparison. The find-prime-numbers test shows 1044 against 620, a 40.6% swing. These two results are outliers in an otherwise Threadripper-dominated dataset, but they are significant outliers. The EPYC's 256 MB L3 and 576.0 GB/s memory bandwidth appear to give it a decisive edge in workloads that iterate over large in-memory datasets.

The overall average benchmark score in the database is 182700 for the Threadripper PRO 9975WX and 160358 for the EPYC 9355P. Both sit at the 98th percentile of all CPUs, so neither is a slow part. The Threadripper's nearest rivals include the AMD EPYC 8534P at 185092 (-1.3%), the Intel Xeon 6740E at 187718 (-2.7%), and the Intel Xeon 6740P at 176227 (3.7%). The EPYC 9355P's nearest rivals are the AMD EPYC 7663 at 161973 (-1%), the Intel Xeon 676X at 158540 (1.1%), and the AMD EPYC 9375F at 162497 (-1.3%).

The data shows a processor that is faster in 15 of 17 tests, often by double digits, but a rival that wins the two tests where cache and memory bandwidth dominate. For rendering, compilation, and general workstation throughput, the Threadripper PRO 9975WX is the superior part. For physics simulation and prime-number workloads, the EPYC 9355P is the better choice, and its lower launch MSRP makes it the logical pick for servers that specialize in those tasks.