AMD Ryzen Threadripper PRO 9955WX vs Intel Core Ultra X9 378H Comparison

Head-to-Head Benchmarks

The benchmark data presents a decisive picture: the AMD Ryzen Threadripper PRO 9955WX wins 16 of the 17 recorded head-to-head comparisons, while the Intel Core Ultra X9 378H takes a single narrow victory. The margins, however, tell a more nuanced story than the win count alone.

In Cinebench rendering tests, the AMD processor dominates across the board. The R15 multicore test shows a score of 5996 against Intel's 3281, a delta of 82.7%. The R20 multicore result repeats the pattern with 24987 versus 13672, an 82.8% advantage. R23 multicore follows suit: 59494 against 32553, again 82.8% ahead. Single-core Cinebench results show a similar gap, with R15 single-core at 846 versus 462 (83.1%), R20 single-core at 3527 versus 1929 (82.8%), and R23 single-core at 8399 versus 4595 (82.8%). These consistent deltas suggest a fundamental throughput advantage rather than a workload-specific quirk.

PassMark results amplify the divide in several specialized workloads. Integer math shows the largest proportional gap: 236120 for AMD versus 92603 for Intel, a 155% difference. Extended instructions follow closely at 143.9% (76363 versus 31315). Data compression delivers 920954 against 386591, a 138.2% margin. Random string sorting shows a 123.6% advantage (99813 versus 44648). These are not marginal differences; they indicate a processor operating in a different performance class entirely.

Other PassMark subtests confirm the trend with smaller but still substantial gaps. Multithread performance sits at 67035 versus 38298, a 75% delta. Data encryption shows 44389 versus 29840, a 48.8% advantage. Floating point math records 156215 versus 114500, 36.4% ahead. Physics testing delivers 4156 versus 3404, a 22.1% margin. Even single-thread PassMark, where the AMD advantage narrows to 4530 versus 4453, still favors the Threadripper by 1.7%.

The sole Intel victory comes in the passmark_find_prime_numbers test. Intel scores 357 against AMD's 337, a 5.6% advantage. This is a narrow win in a single algorithmic workload, and it stands isolated against the broader pattern. The data suggests that this specific prime-number search loop favors some characteristic of the Intel core design, but the effect does not carry over to other integer or floating-point workloads.

Architecture Differences

The two processors are built on fundamentally different foundations. The AMD Ryzen Threadripper PRO 9955WX uses the Zen 5 architecture, codenamed Shimada Peak, fabricated on a 4 nm process at TSMC. It contains 16,630 million transistors across a die size of 2x 70.6 mm². The Intel Core Ultra X9 378H, by contrast, uses the Panther Lake codename from the Ultra X9 generation, built on Intel's own 3 nm process. The database records no transistor count or die size for the Intel part.

Core and thread counts reveal a key design divergence. Both processors have 16 cores, but the AMD part supports 32 threads through simultaneous multithreading, while the Intel part runs 16 threads with no SMT. This doubles the logical thread count for AMD, which directly explains much of the multicore benchmark gap. Cache hierarchies also differ sharply. AMD allocates 64 KB of L1 per core and 1 MB of L2 per core, with a shared 64 MB L3 pool. Intel provides 192 KB of L1 per core and 2.5 MB of L2 per core, but only 18 MB of shared L3. The AMD processor carries over three and a half times more L3 cache, which benefits workloads with large working sets.

Clock speeds and power envelopes tell opposite stories. The AMD part runs a 4.50 GHz base clock and 5.40 GHz boost, with a 350 W TDP. The Intel part operates at 2.00 GHz base and 5.00 GHz boost, within a 25 W TDP. The Intel chip is clearly engineered for mobile power efficiency, while the AMD chip is a desktop-class powerhouse. The socket and platform reflect this split: AMD uses Socket sTR5 with 128 PCIe Gen 5 lanes from the CPU, while Intel uses BGA 2540 with only 4 PCIe Gen 5 lanes. Memory support diverges as well: AMD runs eight-channel DDR5 with 409.6 GB/s bandwidth and ECC support, while Intel runs dual-channel LPDDR5X at 153.6 GB/s without ECC. Intel integrates an Arc B390 graphics solution; AMD has no integrated graphics.

Where Each One Wins

The AMD Ryzen Threadripper PRO 9955WX wins in every multicore-heavy scenario recorded in the database. Rendering, compilation-style integer workloads, data compression, encryption, and floating-point math all fall under its dominance. The 32 threads, 64 MB L3 cache, and 409.6 GB/s memory bandwidth give it an overwhelming advantage in throughput-bound tasks. The Cinebench R23 multicore score of 59494, nearly double Intel's 32553, indicates that long-running parallel jobs will finish in roughly half the time. The PassMark multithread result of 67035 confirms this scaling.

The AMD part also wins single-thread performance in most tests, but by a much smaller margin. The 1.7% PassMark single-thread advantage and the 82.8% Cinebench R23 single-core advantage are inconsistent. The Cinebench single-core gap is large, but the PassMark single-thread gap is nearly negligible. This suggests the AMD core has a substantial clock and IPC advantage in some workloads, while in others the Intel core, despite its lower 2.00 GHz base clock, closes most of the distance. The Intel boost clock of 5.00 GHz, combined with its 3 nm process, likely explains its competitiveness in lightly threaded PassMark tests.

The Intel Core Ultra X9 378H wins the find_prime_numbers test by 5.6%. This is the only recorded benchmark where Intel surpasses AMD. The result implies that the specific loop structure of prime-number searching, possibly involving branch-heavy or latency-sensitive operations, aligns better with Intel's core design. It is a narrow win, but it demonstrates that the Intel part is not universally slower.

Power-constrained environments favor the Intel part by design, though the database does not record direct efficiency benchmarks. The 25 W TDP against AMD's 350 W TDP means the Intel chip can operate in thin-and-light mobile systems where a 350 W desktop processor cannot physically fit. The integrated Arc B390 graphics also enables systems without a discrete GPU, which the AMD part cannot do.

FAQ

Q: How much faster is the AMD processor in Cinebench R23 multicore?

A: The AMD Ryzen Threadripper PRO 9955WX scores 59494, while the Intel Core Ultra X9 378H scores 32553, giving AMD an 82.8% advantage in that test.

Q: Does the Intel processor win any benchmark?

A: Yes, the Intel Core Ultra X9 378H wins passmark_find_prime_numbers with a score of 357 against AMD's 337, a 5.6% advantage.

Q: What is the difference in thread counts?

A: Both processors have 16 cores, but the AMD part supports 32 threads, while the Intel part supports 16 threads.

Q: What are the TDP ratings for each processor?

A: The AMD Ryzen Threadripper PRO 9955WX has a TDP of 350 W, while the Intel Core Ultra X9 378H has a TDP of 25 W.

Q: Which processor supports ECC memory?

A: The AMD Ryzen Threadripper PRO 9955WX supports ECC memory. The Intel Core Ultra X9 378H does not.

Q: What is the memory bandwidth difference?

A: The AMD processor provides 409.6 GB/s through eight-channel DDR5, while the Intel processor provides 153.6 GB/s through dual-channel LPDDR5X.

Specification Differences

| Specification | AMD Ryzen Threadripper PRO 9955WX | Intel Core Ultra X9 378H |

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

| Cores | 16 | 16 |

| Threads | 32 | 16 |

| Base Clock | 4.50 GHz | 2.00 GHz |

| Boost Clock | 5.40 GHz | 5.00 GHz |

| TDP | 350 W | 25 W |

| Socket | AMD Socket sTR5 | Intel BGA 2540 |

| Process Node | 4 nm (TSMC) | 3 nm (Intel) |

| Codename | Shimada Peak | Panther Lake |

| L1 Cache | 64 KB per core | 192 KB per core |

| L2 Cache | 1 MB per core | 2.5 MB per core |

| L3 Cache | 64 MB | 18 MB shared |

| Memory Support | DDR5 | LPDDR5X |

| Memory Bus | Eight-channel | Dual-channel |

| Memory Bandwidth | 409.6 GB/s | 153.6 GB/s |

| ECC Memory | Yes | No |

| PCIe Lanes | Gen 5, 128 lanes | Gen 5, 4 lanes |

| Integrated Graphics | N/A | Arc B390 |

| Market Segment | Desktop | Mobile |

| Multiplier Unlocked | Yes | No |

| Transistors | 16,630 million | Not recorded |

| Die Size | 2x 70.6 mm² | Not recorded |

The Verdict

The data positions these processors in entirely different market segments. The AMD Ryzen Threadripper PRO 9955WX is a desktop part with a 350 W TDP, 128 PCIe Gen 5 lanes, eight-channel memory, and 32 threads. It posts a 97th percentile ranking among all CPUs and an average benchmark score of 101041. Its nearest rival, the AMD EPYC 7513, sits just 1.2% ahead, while the EPYC 8324P trails by 2.2%. This is a high-end workstation processor for users who need maximum throughput in rendering, data processing, and compute-heavy tasks.

The Intel Core Ultra X9 378H is a mobile processor with a 25 W TDP, integrated graphics, and 16 threads. It ranks in the 89th percentile with an average score of 47468, placing it near the AMD Ryzen 9 PRO 5945 (0.1% behind) and the Intel Core Ultra 7 265T (0.5% ahead). Its performance class is mainstream mobile, not workstation-class.

Users who require sustained multicore compute, large memory bandwidth, or extensive PCIe connectivity should choose the AMD part. The 82.8% Cinebench R23 multicore advantage and the 155% integer math advantage are decisive for rendering, simulation, and data-heavy workflows. The Intel part suits mobile systems where the 25 W TDP and integrated Arc B390 graphics enable compact designs. The single prime-number test win does not offset the 16-1 benchmark record, but it indicates that the Intel core handles certain branch-heavy loops competently. For desktop workstations, the AMD Ryzen Threadripper PRO 9955WX is the clear choice. For mobile efficiency with a 5.00 GHz boost capability, the Intel Core Ultra X9 378H has its place. The two processors are not direct competitors; they serve different physical and thermal envelopes.