AMD EPYC 7551 vs Intel Core i9-9940X Comparison

FAQ

Q: Which processor has more cores and threads?

A: The AMD EPYC 7551 is equipped with 32 cores and 64 threads, while the Intel Core i9-9940X has 14 cores and 28 threads. The EPYC's thread count is more than double that of the Core i9.

Q: In the head-to-head benchmark results, which processor wins the most tests?

A: The Intel Core i9-9940X wins all six recorded head-to-head Cinebench tests. It posts a 7.2% advantage in the R15, R20, and R23 multi-core and single-core runs, with the exact delta varying between 7.1% and 7.2% depending on the workload.

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

A: The AMD EPYC 7551 supports an eight-channel memory bus with a bandwidth of 170.6 GB/s, whereas the Intel Core i9-9940X uses a quad-channel bus at 85.3 GB/s. The EPYC provides double the theoretical memory bandwidth.

Q: Does the Intel Core i9-9940X support ECC memory?

A: No, the Core i9-9940X does not support ECC memory. The AMD EPYC 7551 does support ECC memory, which is a key feature for server and workstation reliability.

Q: What is the process node for both processors?

A: Both the AMD EPYC 7551 and the Intel Core i9-9940X are built on a 14 nm process node. The EPYC is manufactured by GlobalFoundries, while the Core i9 is manufactured by Intel.

Q: What is the average benchmark score for each processor?

A: The AMD EPYC 7551 has an average benchmark score of 6391, while the Intel Core i9-9940X has an average score of 6657. Both sit at the 62nd percentile compared to all CPUs in the database.

Architecture Differences

The AMD EPYC 7551 and Intel Core i9-9940X take fundamentally different architectural approaches. The EPYC 7551, part of the EPYC 7001 series, is built on AMD's Zen architecture with the codename Naples. It uses a 14 nm process from GlobalFoundries and integrates 4,800 million transistors on a 213 mm² die. In contrast, the Core i9-9940X is based on Intel's Skylake architecture, specifically the Skylake-X design, and uses a 14 nm process from Intel with a much larger 484 mm² die.

The core counts diverge sharply. The EPYC 7551 packs 32 cores and 64 threads, making it a high-density server part. The Core i9-9940X offers 14 cores and 28 threads, a configuration aimed at desktop enthusiasts. This difference in core count is not just a matter of raw numbers; it reflects the intended workloads. The EPYC is designed for parallel server tasks, while the Core i9 targets latency-sensitive desktop applications.

Cache hierarchies also differ. The EPYC 7551 has 96 KB of L1 cache per core, 512 KB of L2 cache per core, and a 64 MB shared L3 cache. The Core i9-9940X has 64 KB of L1 per core, 1 MB of L2 per core, and a 19.25 MB shared L3 cache. The EPYC's larger L3 pool is a direct consequence of its many-core design, whereas the Core i9's smaller L3 is typical of Intel's desktop HEDT lineup.

Memory support is another major architectural split. The EPYC 7551 uses an eight-channel DDR4 memory bus with a peak bandwidth of 170.6 GB/s and supports ECC memory, which is essential for error-correcting server workloads. The Core i9-9940X uses a quad-channel DDR4 bus at 85.3 GB/s and lacks ECC support. The EPYC's memory subsystem is built for throughput and reliability, while the Core i9's is optimized for lower latency and simpler desktop configurations.

Both processors use PCIe Gen 3, but the Core i9-9940X provides 44 lanes from the CPU, a detail in the database. The EPYC 7551's PCIe configuration is not specified in the recorded data, though its server socket, AMD Socket SP3, is designed for multi-socket platforms. The Core i9 uses Intel Socket 2066, a single-socket HEDT platform.

Clock speeds show a clear tradeoff. The EPYC 7551 has a base clock of 2000 MHz and a boost clock of 3000 MHz, reflecting its power-efficient server orientation. The Core i9-9940X runs at a base clock of 3300 MHz and boosts to 4500 MHz, giving it a substantial single-thread frequency advantage. TDPs are 180 W for the EPYC and 165 W for the Core i9, so the EPYC draws slightly more power despite lower clocks, a cost of its massive core count.

The production status differs as well. The EPYC 7551 is listed as active, while the Core i9-9940X is end-of-life. The EPYC's release date is 2017-06-28, and the Core i9's release date is 2018-10-18, so the Intel part arrived over a year later.

Where Each One Wins

The benchmark data favors the Intel Core i9-9940X across every Cinebench test recorded. In single-core workloads, the Core i9 wins decisively. Its R15 single-core score is 338 versus 314 for the EPYC, a 7.1% lead. The R20 single-core run shows 1411 versus 1309, and the R23 single-core run shows 3361 versus 3119, both at a 7.2% margin. The Core i9's higher base and boost clocks, 3300 MHz and 4500 MHz, explain this advantage. For tasks that rely on a single thread, such as legacy applications, lightweight scripting, or lightly threaded games, the Core i9 is the stronger choice.

Multi-core results also lean toward the Core i9, despite its lower core count. In Cinebench R15 multi-core, the Core i9 scores 2400 against the EPYC's 2227, a 7.2% lead. The R20 multi-core test shows 10000 versus 9280, and the R23 multi-core test shows 23810 versus 22096, both at 7.2% margins. This is a notable outcome: the EPYC has 32 cores, more than double the Core i9's 14, yet it trails in these multi-threaded renders. The data suggests that the Core i9's higher frequency and per-core efficiency outweigh the EPYC's raw core count in Cinebench's scaling characteristics.

The AMD EPYC 7551 wins in areas not captured by the Cinebench suite. Its memory bandwidth, 170.6 GB/s versus 85.3 GB/s, is double that of the Core i9. For workloads that are memory-bandwidth bound, such as large database scans, in-memory analytics, or high-performance computing simulations, the EPYC's eight-channel memory subsystem provides a structural advantage. Its ECC memory support adds a reliability layer that the Core i9 cannot offer, making the EPYC suitable for error-sensitive server environments. The EPYC's 32 cores also provide more parallel headroom for heavily threaded server workloads, even if Cinebench does not reflect that advantage.

The Core i9-9940X is the better fit for desktop and workstation users who prioritize clock speed and per-thread performance. Its 44 PCIe Gen 3 lanes support multiple GPUs and NVMe drives, and its end-of-life status does not diminish its current benchmark standing. The EPYC 7551, with its active production status and server market segment, is built for data center deployments where ECC, memory bandwidth, and core density matter more than raw Cinebench scores.

Specification Differences

| Specification | AMD EPYC 7551 | Intel Core i9-9940X |

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

| Cores | 32 | 14 |

| Threads | 64 | 28 |

| Base Clock | 2000 MHz | 3300 MHz |

| Boost Clock | 3000 MHz | 4500 MHz |

| TDP | 180 W | 165 W |

| Socket | AMD Socket SP3 | Intel Socket 2066 |

| Architecture | Zen | Skylake |

| Codename | Naples | Skylake-X |

| Foundry | GlobalFoundries | Intel |

| Die Size | 213 mm² | 484 mm² |

| Transistors | 4,800 million | Not recorded |

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

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

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

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

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

| ECC Memory | Yes | No |

| Market Segment | Server/Workstation | Desktop |

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

| Part Number | PS7551BDVIHAF | SREZ5 |

The launch MSRP for the Intel Core i9-9940X is $1387. The AMD EPYC 7551 has no launch MSRP recorded in the database.

Head-to-Head Benchmarks

The Cinebench suite provides the only direct head-to-head comparisons in the database, and the Intel Core i9-9940X wins every one of the six recorded tests. The margins are consistent, hovering near 7.2% across the board.

In Cinebench R15 multi-core, the Core i9-9940X scores 2400 against the EPYC 7551's 2227. The delta is 7.2% in favor of Intel. This result is striking because the EPYC has 32 cores and 64 threads, while the Core i9 has 14 cores and 28 threads. The Core i9's 3300 MHz base clock and 4500 MHz boost clock appear to overcome the EPYC's core-count advantage in this rendering workload.

The R15 single-core test shows a similar pattern. The Core i9 scores 338, the EPYC scores 314, and the delta is 7.1%. This is the smallest margin of the six tests, but it still favors Intel. The Core i9's higher clock speeds are the obvious driver, as single-core performance in Cinebench is largely frequency-bound.

Cinebench R20 multi-core repeats the story. The Core i9-9940X records 10000 points, while the EPYC 7551 records 9280 points, a 7.2% difference. The R20 single-core test shows 1411 for the Core i9 and 1309 for the EPYC, also a 7.2% gap. The consistency of these deltas across different Cinebench versions indicates a stable performance relationship between the two processors, not a workload-specific anomaly.

The newest test, Cinebench R23, confirms the trend. Multi-core scores are 23810 for the Core i9 and 22096 for the EPYC, a 7.2% lead for Intel. Single-core scores are 3361 versus 3119, again a 7.2% margin. Across all six head-to-head tests, the Core i9's smallest win is 7.1% and its largest is 7.2%, showing a tightly clustered performance gap.

The EPYC 7551 has zero head-to-head wins in the database, while the Core i9-9940X has six. However, the average benchmark scores provide additional context. The Core i9's average is 6657, and its nearest rivals include the AMD Ryzen Threadripper 2950X at 6647 (a 0.1% delta) and the Intel Core i5-13400E at 6638 (0.3%). The EPYC's average is 6391, with its closest rival being the Intel Core i9-10920X at 6347 (0.7%). Both processors sit at the 62nd percentile among all CPUs, so they occupy a similar tier in the overall performance distribution, even though the Core i9 holds a consistent edge in direct comparisons.