CPU Comparison

The AMD EPYC 7551 and Intel Atom x7405C represent two entirely different philosophies in processor design. The EPYC 7551 is a 32-core server behemoth from AMD’s 7001 series, built for heavy throughput, while the Atom x7405C is a 4-core mobile chip from Intel’s Amston Lake family, designed for efficiency and compact systems. Benchmark data shows a complete sweep for the EPYC 7551 in the head-to-head Cinebench tests, but the Atom’s average benchmark score tells a more nuanced story about its specialized strengths. This analysis breaks down where each processor wins, the architectural gulf between them, and what the numbers actually mean for potential use cases.

Where Each One Wins

The data is unambiguous in rendering a verdict on raw compute: the AMD EPYC 7551 wins every single head-to-head benchmark listed, taking all 6 wins with zero for the Intel Atom x7405C. The magnitude of these victories is staggering, with deltaPct values hovering around 398-406% in the EPYC’s favor across all Cinebench R15, R20, and R23 tests, both single-core and multi-core. The EPYC 7551 delivers a 399.3% lead in Cinebench R15 multi-core (2227 vs 446) and a 406.5% lead in the same test’s single-core variant (314 vs 62). In multi-core workloads, this is exactly what you would expect from a 32-core, 64-thread processor facing a 4-core, 4-thread part.

However, the Atom x7405C’s strength does not appear in the head-to-head Cinebench comparisons, it appears in its broader benchmark portfolio and its efficiency profile. The Atom’s average benchmark score of 6568 actually exceeds the EPYC’s 6391 average, and both sit at the 62nd percentile among all CPUs. The Atom achieves this with PassMark tests that are absent from the EPYC’s data set, including data compression (56317), data encryption (4004), integer math (14669), and floating-point math (9063). In these specialized workloads, the Atom’s 4 Gracemont cores, boosting to 3.40 GHz, produce respectable numbers. The Atom also wins decisively on power: its 12W TDP is a fraction of the EPYC’s 180W TDP, making it the clear choice for power-constrained or fanless designs where raw performance is secondary.

Architecture Differences

The architectural gap between these two processors is cavernous. The EPYC 7551 uses AMD’s Zen architecture, codenamed Naples, built on a 14 nm process at GlobalFoundries. It packs 4,800 million transistors into a 213 mm² die. The Atom x7405C uses Intel’s Amston Lake architecture with Gracemont cores, built on a 10 nm process at Intel, with transistor count and die size not listed. The EPYC is part of the EPYC 7001 series, while the Atom belongs to the Atom generation (Gracemont).

Core counts and threading diverge sharply: the EPYC 7551 offers 32 cores and 64 threads, while the Atom provides 4 cores and 4 threads, no simultaneous multithreading. Clock speeds tell a similar story of differing priorities: the EPYC’s base clock is 2000 MHz with a 3.00 GHz boost, while the Atom starts lower at 1.70 GHz but boosts higher to 3.40 GHz, emphasizing burst responsiveness over sustained throughput. Cache hierarchies are also radically different. The EPYC 7551 has 64 MB of shared L3 cache and 512 KB of L2 per core, while the Atom has 6 MB of shared L3 and 2 MB of shared L2. Both have 96 KB of L1 per core.

Memory support underscores their divergent roles. The EPYC 7551 runs DDR4 on an eight-channel memory bus with 170.6 GB/s of bandwidth and ECC support. The Atom x7405C supports both DDR4 and DDR5 but on a single-channel bus, delivering only 38.4 GB/s, and notably lacks ECC memory support. PCIe connectivity also differs: the EPYC offers Gen 3 lanes, while the Atom provides Gen 3 with 9 lanes (CPU only). The EPYC uses AMD Socket SP3, while the Atom uses Intel BGA 1264. The EPYC has an unlocked multiplier; the Atom is locked. Integrated graphics are absent on the EPYC and listed as "N/A" on the Atom. The EPYC launched in 2017, while the Atom arrived in 2024.

Head-to-Head Benchmarks

The Cinebench head-to-head results are a masterclass in processor scaling. In Cinebench R15 multi-core, the EPYC 7551 scores 2227 against the Atom’s 446, a 399.3% advantage. Single-core R15 shows an even larger relative gap: 314 vs 62, a 406.5% delta. Moving to Cinebench R20, the EPYC posts 9280 multi-core versus 1862 for the Atom (398.4% lead), and 1309 single-core versus 262 (399.6% lead). Cinebench R23 continues the pattern: 22096 vs 4435 multi-core (398.2% advantage) and 3119 vs 626 single-core (398.2% advantage).

The consistent ~400% delta across every Cinebench iteration, regardless of single-core or multi-core, is remarkable. It suggests that the Atom’s high boost clock of 3.40 GHz cannot compensate for the EPYC’s architectural efficiency per clock in these rendering workloads. Even in single-core tests, where the Atom’s boost advantage should help, the EPYC’s Zen core is roughly 4x faster. The data indicates that the EPYC 7551’s 3.00 GHz boost clock, while lower on paper, delivers vastly superior instructions per clock in Cinebench’s render paths.

The Atom’s rival comparisons further contextualize its position. Its nearest rival list includes the Intel Core i5-13500E (avg score 6586, delta -0.3%), Intel Core i9-7960X (6533, +0.5%), Intel Core i9-10940X (6605, -0.6%), and Intel Pentium Gold G6405 (6605, -0.6%). These are all mainstream or high-end desktop processors, yet the Atom’s average benchmark score sits right beside them. The EPYC 7551, meanwhile, is bracketed by the Intel Core i9-10920X (6347, +0.7%), Intel Core i7-12800HE (6467, -1.2%), Intel Xeon D-2796TE (6510, -1.8%), and Intel Xeon W-2191B (6531, -2.1%). This means the Atom x7405C, despite its 4-core design and 12W TDP, produces an average benchmark score comparable to 32-core server parts from the EPYC’s era.

The Verdict

The data dictates a clear split. For any workload that relies on Cinebench-style rendering or multi-threaded compute, the AMD EPYC 7551 is the only choice. It dominates every head-to-head benchmark with roughly 400% margins, offers 32 cores and 64 threads, eight-channel memory bandwidth of 170.6 GB/s, and ECC support, all within a 180W TDP. This is a server/workstation processor that delivers massive parallel throughput for virtualization, scientific computing, or heavy content creation. Its 62nd percentile ranking and average score of 6391 place it in solid company with contemporary Intel Core i9 and Xeon parts.

The Intel Atom x7405C earns its place in a different arena. With a 12W TDP, it is designed for mobile or embedded systems where power draw is the primary constraint. Its 4 cores and 4 threads, single-channel memory bus, and 38.4 GB/s bandwidth are not competitive for heavy compute, but its PassMark numbers, including 56317 in data compression and 14669 in integer math, show it can handle specific, lightweight tasks competently. Its average benchmark score of 6568, which edges out the EPYC’s 6391, suggests that in a mixed workload suite that includes its strengths, the Atom punches well above its core count. The launch MSRP is $57.

Choose the EPYC 7551 if you need raw processing power, multi-threaded rendering, or enterprise-grade memory features. Choose the Atom x7405C if you need a low-power, low-cost, compact solution for embedded or mobile applications where efficiency trumps performance. Neither processor is a substitute for the other; they serve entirely different markets, and the benchmark data reflects that divergence clearly.

FAQ

Q: Which processor has more cores and threads?

A: The AMD EPYC 7551 has 32 cores and 64 threads, while the Intel Atom x7405C has 4 cores and 4 threads.

Q: How does the EPYC 7551 compare to the Atom x7405C in Cinebench R23 multi-core?

A: The EPYC 7551 scores 22096, which is 398.2% higher than the Atom’s 4435.

Q: Does the Atom x7405C support ECC memory?

A: No, the Atom x7405C does not support ECC memory, while the EPYC 7551 does.

Q: What is the TDP difference between the two processors?

A: The EPYC 7551 has a TDP of 180W, while the Atom x7405C has a TDP of 12W.

Q: Which processor has a higher average benchmark score?

A: The Atom x7405C has an average benchmark score of 6568, which is higher than the EPYC 7551’s 6391. Both are at the 62nd percentile.

Q: What is the memory bandwidth of the EPYC 7551?

A: The EPYC 7551 has a memory bandwidth of 170.6 GB/s, compared to the Atom’s 38.4 GB/s.