Intel Core i9-10920X vs Intel Core i9-9940X Comparison

The Verdict

The benchmark data splits these two Intel HEDT processors along clear lines. The Intel Core i9-9940X wins six of eight head-to-head tests, taking every Cinebench round (R15, R20, R23) in both single-core and multi-core workloads. Its edge in those tests is consistent at 8.0 to 8.2 percent across all six Cinebench disciplines. The Intel Core i9-10920X, however, wins both Geekbench tests, with a 6.7 percent lead in multi-core and a substantial 14 percent lead in single-core.

For users whose workloads resemble Cinebench, the i9-9940X is the stronger pick. Its additional two cores and 28 threads over the i9-10920X's 24 threads translate directly into higher multi-core scores. For single-threaded Cinebench tasks, the i9-9940X also leads, which is notable given the i9-10920X has a higher boost clock. The Geekbench results tell the opposite story: the i9-10920X outperforms the older chip in both metrics, with the single-core gap being the largest difference recorded between the two.

The average benchmark score also favors the i9-9940X. It sits at 6657, roughly 4.9 percent above the i9-10920X's average of 6347. Both processors occupy the 62nd percentile among all CPUs in the database, indicating they perform in the same general tier despite the different benchmark outcomes. The production status adds another layer: the i9-9940X is listed as end-of-life while the i9-10920X remains active. That makes the i9-9940X a legacy buy, though its performance data remains competitive.

Architecture Differences

The two chips share the same Intel Socket 2066, 14 nm process node, and Intel as the foundry. The core architectures diverge: the i9-10920X uses Cascade Lake (Cascade Lake-X), while the i9-9940X uses Skylake (Skylake-X). The i9-9940X has a larger die at 484 mm²; the i9-10920X has no recorded die size. Both have identical cache layouts: 64 KB L1 per core, 1 MB L2 per core, and 19.25 MB shared L3.

Memory support matches on both sides: DDR4 with a quad-channel bus. The i9-9940X records a memory bandwidth of 85.3 GB/s, while the i9-10920X has no bandwidth figure in the database. PCIe differs: the i9-10920X lists Gen 3 with no lane count, while the i9-9940X lists Gen 3 with 44 lanes (CPU only). Neither supports ECC memory, and both have no integrated graphics. Both have unlocked multipliers, and both target the desktop market segment.

The i9-9940X carries a part number (SREZ5) and a recorded launch MSRP of $1387, while the i9-10920X has neither in the database. The i9-9940X launched on 2018-10-18, exactly one year before the i9-10920X's 2019-10-18 release. That year gap explains the architecture shift from Skylake to Cascade Lake, though the process node stayed at 14 nm.

FAQ

Q: Which processor has more cores?

A: The Intel Core i9-9940X has 14 cores and 28 threads, while the Intel Core i9-10920X has 12 cores and 24 threads.

Q: Why does the i9-9940X win all Cinebench tests despite having a lower boost clock?

A: The i9-9940X's boost clock is 4.50 GHz versus 4.80 GHz for the i9-10920X, but it has two additional cores. The Cinebench multi-core tests reward the extra core count, and the single-core Cinebench results still favor the i9-9940X by 8.0 to 8.2 percent, suggesting the Skylake architecture delivers higher per-thread performance in those specific workloads.

Q: Is the i9-10920X better in any benchmark?

A: Yes. It wins Geekbench multi-core by 6.7 percent (11165 vs 10466) and Geekbench single-core by 14 percent (1673 vs 1468). These are the only two tests where it beats the i9-9940X.

Q: What is the average benchmark score difference?

A: The i9-9940X averages 6657 across all recorded benchmarks, while the i9-10920X averages 6347. That is a difference of 310 points, or roughly 4.9 percent in favor of the i9-9940X.

Q: Are both processors still in production?

A: No. The i9-9940X is marked end-of-life, while the i9-10920X is listed as active production.

Q: Do both use the same memory configuration?

A: Both support DDR4 memory with a quad-channel bus. The i9-9940X has a recorded memory bandwidth of 85.3 GB/s; the i9-10920X has no bandwidth figure in the database. Neither supports ECC memory.

Specification Differences

| Specification | Intel Core i9-10920X | Intel Core i9-9940X |

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

| Cores | 12 | 14 |

| Threads | 24 | 28 |

| Base clock | 3.50 GHz | 3.30 GHz |

| Boost clock | 4.80 GHz | 4.50 GHz |

| Architecture | Cascade Lake | Skylake |

| Codename | Cascade Lake-X | Skylake-X |

| Generation | Core i9 (X-Series 10th Gen) | Core i9 (X-Series 9th Gen) |

| Die size | Not recorded | 484 mm² |

| Memory bandwidth | Not recorded | 85.3 GB/s |

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

| Production status | Active | End-of-life |

| Release date | 2019-10-18 | 2018-10-18 |

| Part number | Not recorded | SREZ5 |

| Launch MSRP | Not recorded | $1387 |

Identical fields include TDP (165 W for both), socket (Intel Socket 2066), process node (14 nm), cache hierarchy (64 KB L1, 1 MB L2, 19.25 MB L3), memory support (DDR4), memory bus (quad-channel), ECC support (false on both), integrated graphics (none on both), market segment (Desktop), and multiplier lock (unlocked on both).

Head-to-Head Benchmarks

The i9-9940X dominates the Cinebench suite with a uniform 8.2 percent lead in multi-core tests. In Cinebench R15 multi-core, it scores 2400 against 2203; in R20 multi-core, 10000 against 9181; in R23 multi-core, 23810 against 21861. The single-core Cinebench results show a slightly narrower margin of 8.0 percent in R15 (338 vs 311) and 8.2 percent in both R20 (1411 vs 1296) and R23 (3361 vs 3086). This consistency across three Cinebench versions, spanning different rendering workloads, points to a stable architectural advantage for the 14-core chip in these specific tasks.

The i9-10920X counters in Geekbench with a 6.7 percent multi-core win (11165 vs 10466) and a 14 percent single-core win (1673 vs 1468). The single-core Geekbench gap is the largest percentage difference in the entire head-to-head set, more than doubling the i9-9940X's Cinebench single-core margin. The multi-core Geekbench result is also notable because it flips the Cinebench outcome: the 12-core i9-10920X beats the 14-core i9-9940X in a multi-threaded test, which suggests the Geekbench workload responds differently to the Cascade Lake architecture's features.

Looking at the overall win count, the i9-9940X takes six wins to the i9-10920X's two. The average benchmark score aligns with that tally, with the i9-9940X at 6657 versus 6347. However, the percentile ranking tells a different story: both sit at the 62nd percentile among all CPUs, meaning their overall standing in the database is effectively equal despite the head-to-head differences.

Where Each One Wins

The Intel Core i9-9940X wins in rendering and compute tasks that resemble Cinebench. Its 8.2 percent multi-core lead across all three R15/R20/R23 versions means users running CPU-based rendering, video encoding, or scientific simulations with similar thread scaling will see measurable gains. The single-core Cinebench wins, though smaller at 8.0 to 8.2 percent, also make it the better choice for lightly threaded workloads in that test family. The two extra cores and four extra threads provide the raw parallel throughput that Cinebench rewards.

The Intel Core i9-10920X wins in Geekbench-style workloads. Its 14 percent single-core advantage is the standout result, indicating better per-thread performance in tasks that Geekbench measures. The 6.7 percent multi-core win is equally significant because it shows the architecture can outperform a higher-core-count chip when the workload is structured differently. Users running productivity suites, general desktop applications, or mixed workloads that align with Geekbench's test patterns would prefer this chip. Its active production status is also a practical advantage over the end-of-life i9-9940X, though that is a supply consideration rather than a performance metric.

The decision ultimately rests on the workload. Cinebench-heavy use cases favor the i9-9940X by a consistent margin. Geekbench-oriented tasks favor the i9-10920X, particularly in single-threaded scenarios. The two processors land in the same percentile tier, but their benchmark profiles are distinct enough that choosing one over the other requires knowing which test suite matches the intended application.