AMD EPYC 9175F vs AMD Ryzen 9 9955HX Comparison

FAQ

Q: Which processor has the larger L3 cache?

A: The AMD EPYC 9175F features a shared 512 MB L3 cache, while the AMD Ryzen 9 9955HX has a shared 64 MB L3 cache. This is a significant difference in cache capacity between the two Zen 5 parts.

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

A: The Ryzen 9 9955HX scores 4393 in the Passmark single-thread test, which is 3.1% higher than the EPYC 9175F’s score of 4256. This gives the mobile chip a narrow win in that specific benchmark.

Q: What is the biggest performance gap between the two in the head-to-head results?

A: The largest delta is in the Passmark physics test, where the EPYC 9175F wins by 267.1% (9984 vs 2720). The Cinebench R23 single-core test shows a similar gap, with the EPYC leading by 263.2% (7895 vs 2174).

Q: Do both processors support ECC memory?

A: Yes, both the AMD EPYC 9175F and the AMD Ryzen 9 9955HX have ECC memory support listed in their specifications.

Q: Which processor has a higher base clock speed?

A: The EPYC 9175F has a base clock of 4.20 GHz, significantly higher than the Ryzen 9 9955HX’s 2.50 GHz base clock. However, the Ryzen 9 9955HX has a higher boost clock at 5.40 GHz compared to 5.00 GHz for the EPYC.

Q: How do the processors differ in memory bus width?

A: The EPYC 9175F uses a twelve-channel memory bus with 576.0 GB/s bandwidth, whereas the Ryzen 9 9955HX uses a dual-channel bus with 89.6 GB/s bandwidth. This is a major architectural divergence.

The Verdict

The data presents a clear split: the AMD EPYC 9175F dominates the Ryzen 9 9955HX in most compute-heavy workloads, winning 12 of the 15 head-to-head benchmarks. Its victories include massive margins in Cinebench R23 multi-core (55923 vs 37159, a 50.5% lead) and single-core (7895 vs 2174, a 263.2% lead). The EPYC also leads in all Passmark sub-tests except single-thread, with deltas ranging from 3.4% in integer math to 267.1% in physics.

The Ryzen 9 9955HX, meanwhile, takes only 3 wins: Cinebench R15 multi-core (5905 vs 5636, a 4.6% edge) and both Passmark single-thread listings (4393 vs 4256, a 3.1% edge). These are narrow margins, suggesting that in light-threaded or certain legacy multi-core scenarios, the mobile chip can hold its own. Its 55W TDP and unlocked multiplier make it an interesting part for mobile enthusiasts, but the benchmark data shows it trails the EPYC in raw throughput.

Who should pick which? The EPYC 9175F is the choice for server and workstation deployments where multi-threaded performance, cache capacity, and memory bandwidth are paramount. Its 96th percentile ranking among all CPUs and 512 MB L3 cache make it a data-center workhorse. The Ryzen 9 9955HX, also in the 96th percentile, is better suited for high-end mobile systems where the 5.40 GHz boost clock and unlocked multiplier offer flexibility, but only if the workload tolerates its lower multi-core scores and 64 MB L3 cache. For anyone prioritizing maximum compute density, the EPYC is the clear winner.

Head-to-Head Benchmarks

The EPYC 9175F’s most decisive victories come in single-core and physics tests. In Cinebench R23 single-core, the EPYC scores 7895 against the Ryzen’s 2174—a 263.2% advantage. Passmark physics shows a similar story: 9984 vs 2720, a 267.1% delta. These results suggest that the EPYC’s higher base clock (4.20 GHz) and server-tier design translate into far superior per-thread performance in these specific benchmarks, despite the Ryzen’s higher boost clock.

Multi-threaded workloads also favor the EPYC, though by smaller margins. In Cinebench R23 multi-core, the EPYC leads with 55923 vs 37159, a 50.5% difference. Passmark multi-thread shows a 20.4% gap (67634 vs 56171), and Passmark data compression has the EPYC ahead by 18.5% (867186 vs 731998). The EPYC also wins in data encryption (42297 vs 37330, +13.3%), extended instructions (70529 vs 57946, +21.7%), and random string sorting (95783 vs 77890, +23%). These are consistent, meaningful margins that point to the EPYC’s superior memory bandwidth (576.0 GB/s vs 89.6 GB/s) and larger cache playing a role in data-heavy tasks.

The Ryzen 9 9955HX’s wins are less dramatic but still notable. Its Cinebench R15 multi-core score of 5905 edges out the EPYC’s 5636 by 4.6%, a rare multi-core victory for the mobile part. In Passmark single-thread, the Ryzen scores 4393 vs 4256, a 3.1% lead. These results indicate that in some legacy or light-threaded workloads, the Ryzen’s 5.40 GHz boost clock can overcome the EPYC’s architectural advantages. However, these are the only bright spots in an otherwise one-sided comparison.

Specification Differences

The core and thread counts are identical: both parts feature 16 cores and 32 threads. The clocks differ notably, with the EPYC 9175F running a 4.20 GHz base and 5.00 GHz boost, while the Ryzen 9 9955HX runs a 2.50 GHz base and 5.40 GHz boost. The TDP is another stark contrast—the EPYC draws 320W compared to the Ryzen’s 55W, reflecting their different market segments (Server/Workstation vs Mobile).

Socket and platform details diverge completely. The EPYC uses AMD Socket SP5, while the Ryzen uses AMD Socket FL1. PCIe lanes also differ: the EPYC offers Gen 5 with 128 lanes (CPU only), whereas the Ryzen provides Gen 5 with 28 lanes (CPU only). The EPYC has no integrated graphics, but the Ryzen includes a Radeon 610M iGPU. The multiplier is locked on the EPYC but unlocked on the Ryzen, giving overclockers more freedom with the mobile chip.

Memory configuration is a major differentiator. The EPYC supports twelve-channel DDR5 with 576.0 GB/s bandwidth, while the Ryzen supports dual-channel DDR5 with 89.6 GB/s. Both support ECC memory. The EPYC’s release date is 2024-10-09, with a launch MSRP of $4256; the Ryzen’s release date is 2025-01-05, with no launch MSRP listed.

Architecture Differences

Both processors are built on Zen 5 architecture, but they come from different families and codenames. The EPYC 9175F is part of the EPYC 9005 series (codename Turin), while the Ryzen 9 9955HX belongs to the 9000 series (codename Fire Range). Both use a 4 nm process node from TSMC, but the transistor counts diverge sharply: the EPYC packs 133,040 million transistors across a die size of 16x 70.6 mm², whereas the Ryzen has 16,630 million transistors on a 2x 70.6 mm² die.

Cache hierarchy is a key architectural difference. Both have 80 KB L1 per core and 1 MB L2 per core, but the L3 cache is vastly different: the EPYC has 512 MB shared, while the Ryzen has 64 MB shared. This 8x difference in L3 likely contributes to the EPYC’s dominance in data compression, encryption, and other cache-sensitive workloads.

The memory controller and I/O are also architecturally distinct. The EPYC’s twelve-channel memory bus supports 576.0 GB/s, while the Ryzen’s dual-channel bus supports 89.6 GB/s—a 6.4x bandwidth advantage for the server chip. The EPYC also offers 128 PCIe Gen 5 lanes versus 28 on the Ryzen, reflecting its role in high-density server environments. The Ryzen’s integrated Radeon 610M graphics is a feature the EPYC lacks, as expected for a mobile part. Both are active in production, but the EPYC’s launch MSRP of $4256 and server-grade specs position it as a data-center part, while the Ryzen’s 55W TDP and unlocked multiplier target high-performance mobile systems.