AMD EPYC 7551 vs Intel Core i9-7940X Comparison

The Verdict

The benchmark data is unusually one-sided. Across six Cinebench tests, the AMD EPYC 7551 wins every single one, ranging from a 2.9% to a 3% advantage over the Intel Core i9-7940X. There is no workload category in this dataset where the Intel part comes out ahead. The EPYC 7551’s average benchmark score of 6391 places it in the 62nd percentile of all CPUs, while the i9-7940X’s 6147 average sits at the 61st percentile. The gap is narrow but consistent.

Who should pick which? The data points to the EPYC 7551 for anyone prioritizing raw multi-threaded throughput. Its 32 cores and 64 threads overwhelm the i9-7940X’s 14 cores and 28 threads in every multicore test. The EPYC also wins the single-core tests, though by a smaller margin. The i9-7940X’s only advantages are qualitative: it is a desktop part with a quad-channel memory bus and an unlocked multiplier, making it a more flexible overclocking platform. But strictly from benchmark scores, the EPYC 7551 is the faster processor.

For a desktop enthusiast building a high-end workstation, the i9-7940X offers a more familiar ecosystem with a 165W TDP versus the EPYC’s 180W. However, the performance data shows no scenario where the Intel chip wins. For a server or workstation buyer who values ECC memory support and eight-channel memory bandwidth, the EPYC 7551 is the clear choice. The data is not close enough to call this a trade-off; it is a sweep.

FAQ

Q: Which processor has more cores and threads?

A: The AMD EPYC 7551 has 32 cores and 64 threads. The Intel Core i9-7940X has 14 cores and 28 threads. That is more than double the core count on the AMD side.

Q: Does the EPYC 7551 win every benchmark in the head-to-head comparison?

A: Yes. The EPYC 7551 wins all six head-to-head Cinebench tests, with deltas of -3% in multicore tests and -2.9% in single-core tests (negative deltaPct indicates the EPYC wins). The Intel part has zero wins in this dataset.

Q: What is the difference in memory bandwidth between the two?

A: The EPYC 7551 supports eight-channel memory with a bandwidth of 170.6 GB/s. The i9-7940X supports quad-channel memory with a bandwidth of 85.3 GB/s. The EPYC offers exactly double the memory bandwidth.

Q: Does the Intel chip support ECC memory?

A: No. The i9-7940X has no ECC memory support. The EPYC 7551 does support ECC memory, which is typical for its server/workstation market segment.

Q: What are the cache sizes for each processor?

A: The i9-7940X has 64 KB of L1 per core, 1 MB of L2 per core, and 19.25 MB of shared L3. The EPYC 7551 has 96 KB of L1 per core, 512 KB of L2 per core, and 64 MB of shared L3. The EPYC has a much larger L3 cache.

Q: What is the transistor count and die size difference?

A: The EPYC 7551 has 4,800 million transistors on a 213 mm² die, fabricated by GlobalFoundries. The i9-7940X has no listed transistor count but has a larger 484 mm² die, fabricated by Intel. Both use a 14 nm process node.

Architecture Differences

The two processors come from fundamentally different design philosophies. The Intel Core i9-7940X uses the Skylake-X architecture, built on a 14 nm process by Intel’s own foundry. Its die size is 484 mm², which is large for a desktop part. The AMD EPYC 7551 uses the Zen architecture under the Naples codename, also on a 14 nm process, but fabricated by GlobalFoundries. Its die is 213 mm², less than half the size of the Intel chip, yet it packs 4,800 million transistors.

The core topologies differ dramatically. The i9-7940X has 14 cores and 28 threads, while the EPYC 7551 has 32 cores and 64 threads. That core advantage is the primary driver of the EPYC’s multicore performance. The cache hierarchy also favors AMD in total capacity: the EPYC has 96 KB of L1 per core, 512 KB of L2 per core, and a massive 64 MB of shared L3. The Intel part has 64 KB of L1 per core, 1 MB of L2 per core (double the per-core L2), but only 19.25 MB of shared L3.

The memory architecture is another key divergence. The i9-7940X supports quad-channel DDR4 memory with a bandwidth of 85.3 GB/s and no ECC support. The EPYC 7551 supports eight-channel DDR4 memory with a bandwidth of 170.6 GB/s and full ECC support. The EPYC also uses AMD Socket SP3, while the Intel part uses the LGA 2066 socket.

The PCIe implementation also differs: the i9-7940X provides Gen 3 with 44 lanes from the CPU, while the EPYC 7551 lists Gen 3 PCIe but does not specify a lane count in the data. The Intel part has an unlocked multiplier, which is notable for overclocking; the EPYC also has an unlocked multiplier. Production status differs, with the i9-7940X marked as end-of-life and the EPYC 7551 as active.

Specification Differences

| Specification | Intel Core i9-7940X | AMD EPYC 7551 |

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

| Cores | 14 | 32 |

| Threads | 28 | 64 |

| Base Clock | 3.10 GHz | 2000.00 MHz (2.00 GHz) |

| Boost Clock | 4.40 GHz | 3.00 GHz |

| TDP | 165 W | 180 W |

| Socket | Intel Socket 2066 | AMD Socket SP3 |

| Architecture | Skylake | Zen |

| Codename | Skylake-X | Naples |

| Generation | Core i9 (X-Series 7th Gen) | EPYC (Zen (Naples)) |

| Foundry | Intel | GlobalFoundries |

| Die Size | 484 mm² | 213 mm² |

| Transistors | Not listed | 4,800 million |

| L1 Cache | 64 KB (per core) | 96 KB (per core) |

| L2 Cache | 1 MB (per core) | 512 KB (per core) |

| L3 Cache | 19.25 MB (shared) | 64 MB (shared) |

| Memory Bus | Quad-channel | Eight-channel |

| Memory Bandwidth | 85.3 GB/s | 170.6 GB/s |

| ECC Memory | No | Yes |

| PCIe | Gen 3, 44 Lanes (CPU only) | Gen 3 |

| Market Segment | Desktop | Server/Workstation |

| Production Status | End-of-life | Active |

| Release Date | 2017-08-31 | 2017-06-28 |

| Launch MSRP | $1399 | Not listed |

| Part Number | SR3RQ | PS7551BDVIHAF |

Head-to-Head Benchmarks

The Cinebench results tell a consistent story. In Cinebench R15 multicore, the EPYC 7551 scores 2227 against the i9-7940X’s 2161, a 3% advantage. The single-core R15 test shows the EPYC at 314 versus 305, a 2.9% lead. This pattern repeats exactly across newer versions. In Cinebench R20 multicore, the EPYC scores 9280 versus 9006, again a 3% edge. The R20 single-core result is 1309 for the EPYC and 1271 for Intel, a 2.9% difference.

The largest absolute gap appears in Cinebench R23 multicore, where the EPYC scores 22096 and the i9-7940X scores 21444. That is a 652-point difference, though the percentage delta remains at 3%. The R23 single-core test shows 3119 for the EPYC versus 3027 for Intel, another 2.9% gap. The consistency of these deltas across all six tests suggests a systematic performance advantage rather than a workload-specific quirk.

It is importantly the i9-7940X’s boost clock of 4.40 GHz is substantially higher than the EPYC’s 3.00 GHz, yet the EPYC still wins the single-core tests. This indicates that the Zen architecture’s per-core efficiency at lower clocks outperforms Skylake-X’s higher frequency approach in these workloads. The EPYC’s 180W TDP is only 15W higher than the Intel part’s 165W, despite having more than twice the cores, which makes its per-watt performance notably superior.

Looking at the nearest rivals for context, the i9-7940X’s average score of 6147 is within 0.3% of the AMD EPYC 7501’s 6128, and within 1.4% of the Ryzen Threadripper 1950X’s 6231. The EPYC 7551’s average of 6391 puts it 0.7% ahead of the Intel Core i9-10920X’s 6347. These comparisons reinforce that the EPYC 7551 sits slightly higher in the performance hierarchy, even among its closest competitors.

The data is unambiguous: in every benchmark recorded, the AMD EPYC 7551 outperforms the Intel Core i9-7940X by roughly 3% in multicore and 2.9% in single-core. The Intel part’s higher clocks and larger die do not translate into a win. For buyers choosing between these two based purely on benchmark results, the EPYC 7551 is the faster processor across the board.