CPU Comparison

The Intel Core i9-9940X and Intel Atom x7405C occupy opposite ends of Intel’s design spectrum, yet both land at the 62nd percentile of all CPUs in this database. The i9-9940X is a 14-core Skylake-X desktop part aimed at high-throughput workloads, while the Atom x7405C is a 4-core Amston Lake mobile chip built for efficiency. The benchmark data shows a complete sweep: the i9-9940X wins all six shared Cinebench tests, with margins ranging from 436.9% to 445.2%. Despite this, the Atom’s average benchmark score (6568) trails the i9-9940X (6657) by only 1.3%, a gap that highlights how different benchmark suites weight the two parts. This analysis breaks down where each processor excels, the architectural reasons behind those results, and the precise numbers that define the matchup.

Where Each One Wins

The data is unambiguous in shared workloads: the Intel Core i9-9940X wins every head-to-head Cinebench test, from R15 single-core to R23 multi-core. Its multi-core advantage is enormous, with the R23 multi-core score of 23810 versus the Atom’s 4435, a 436.9% lead. The i9-9940X also dominates single-core tests, posting 3361 in R23 single-core against the Atom’s 626, a 436.9% delta. This makes the i9-9940X the clear choice for rendering, simulation, and any task that scales with thread count or requires strong per-core performance, as its 28 threads and 4.50 GHz boost clock deliver.

The Intel Atom x7405C wins no shared benchmarks, but its profile is not without merit. Its PassMark results reveal strengths in specific embedded workloads: a data compression score of 56317, integer math at 14669, and floating-point math at 9063. These numbers, while far below the i9-9940X’s Cinebench output, are respectable for a 12 W part. The Atom’s real advantage is unquantified in this data, its 12 W TDP and active production status suggest it is designed for low-power, always-on systems where the i9-9940X’s 165 W TDP would be impractical. The data shows the Atom is not a competitor in raw compute; its wins are in power efficiency and market longevity, not benchmark scores.

Architecture Differences

The two processors are separated by nearly six years of Intel design philosophy. The Core i9-9940X uses the Skylake-X architecture on a 14 nm process, with a die size of 484 mm². It features 14 cores and 28 threads, with a base clock of 3.30 GHz and boost clock of 4.50 GHz. Its cache hierarchy is per-core: 64 KB L1 and 1 MB L2 per core, plus a shared 19.25 MB L3. The memory subsystem is quad-channel DDR4 with 85.3 GB/s bandwidth, and it offers 44 PCIe Gen 3 lanes. This is a desktop part on Intel Socket 2066, with an unlocked multiplier and launch MSRP of $1387.

The Atom x7405C uses the Amston Lake architecture (codename Amston Lake, generation Atom/Gracemont) on a 10 nm process. It has 4 cores and 4 threads, with a base clock of 1.70 GHz and boost clock of 3.40 GHz. Its cache differs fundamentally: 96 KB L1 per core, 2 MB shared L2, and 6 MB shared L3. Memory support is single-channel DDR4 or DDR5, with 38.4 GB/s bandwidth, and PCIe is limited to 9 Gen 3 lanes. This is a mobile part on Intel BGA 1264, with a locked multiplier and launch MSRP of $57. The process node gap (14 nm vs 10 nm) explains the Atom’s much lower TDP, while the i9-9940X’s larger cache and memory bandwidth support its compute-heavy role.

Head-to-Head Benchmarks

The Cinebench results show a consistent, almost mechanical advantage for the i9-9940X across every version and workload type. In Cinebench R15 multi-core, the i9-9940X scores 2400 against the Atom’s 446, a 438.1% delta. The single-core R15 test shows a 445.2% lead, with 338 versus 62. Moving to R20, the multi-core gap is 437.1% (10000 vs 1862), and single-core is 438.5% (1411 vs 262). The R23 results mirror this pattern: multi-core 436.9% (23810 vs 4435) and single-core 436.9% (3361 vs 626). The consistency of these deltas, all between 436% and 446%, indicates that the i9-9940X’s advantage is structural, rooted in its core count, clock speed, and memory bandwidth, rather than workload-specific.

The single-core margins are particularly telling. The i9-9940X’s 4.50 GHz boost clock is only 1.10 GHz higher than the Atom’s 3.40 GHz, yet the R23 single-core score is 5.4 times higher. This suggests the Skylake-X core is significantly more efficient per clock than the Gracemont core in the Atom, despite the latter being on a newer 10 nm process. The multi-core deltas are even larger, reflecting the 14-core versus 4-core disparity. No shared benchmark shows the Atom winning, and the data offers no scenario where the Atom’s lower power consumption translates into a performance advantage in these tests.

FAQ

Q: Which processor has a higher multi-core score in Cinebench R23?

A: The Intel Core i9-9940X scores 23810, while the Intel Atom x7405C scores 4435, giving the i9-9940X a 436.9% advantage.

Q: How do the single-core scores compare in Cinebench R20?

A: The i9-9940X scores 1411, and the Atom scores 262, a 438.5% lead for the i9-9940X.

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

A: The i9-9940X has a TDP of 165 W, while the Atom x7405C has a TDP of 12 W, a 153 W difference.

Q: Do both processors support the same memory types?

A: No. The i9-9940X supports DDR4 only, with quad-channel memory and 85.3 GB/s bandwidth. The Atom supports both DDR4 and DDR5, but with single-channel memory and 38.4 GB/s bandwidth.

Q: Which processor has more PCIe lanes?

A: The i9-9940X offers 44 PCIe Gen 3 lanes, while the Atom x7405C offers 9 PCIe Gen 3 lanes.

Q: Are both processors currently in production?

A: No. The i9-9940X is end-of-life, with a release date of 2018-10-18. The Atom x7405C is active, with a release date of 2024-04-07.

Specification Differences

The following fields differ between the Intel Core i9-9940X and Intel Atom x7405C:

• Cores: 14 (i9-9940X) vs 4 (Atom x7405C)
• Threads: 28 vs 4
• Base Clock: 3.30 GHz vs 1.70 GHz
• Boost Clock: 4.50 GHz vs 3.40 GHz
• TDP: 165 W vs 12 W
• Socket: Intel Socket 2066 vs Intel BGA 1264
• Architecture: Skylake vs Amston Lake
• Codename: Skylake-X vs Amston Lake
• Generation: Core i9 (X-Series 9th Gen) vs Atom (Gracemont)
• Process Node: 14 nm vs 10 nm
• Die Size: 484 mm² vs null (not specified)
• L1 Cache: 64 KB (per core) vs 96 KB (per core)
• L2 Cache: 1 MB (per core) vs 2 MB (shared)
• L3 Cache: 19.25 MB (shared) vs 6 MB (shared)
• Memory Support: DDR4 vs DDR4, DDR5
• Memory Bus: Quad-channel vs Single-channel
• Memory Bandwidth: 85.3 GB/s vs 38.4 GB/s
• PCIe: Gen 3, 44 Lanes vs Gen 3, 9 Lanes
• Integrated Graphics: null vs N/A
• Market Segment: Desktop vs Mobile
• Production Status: End-of-life vs Active
• Release Date: 2018-10-18 vs 2024-04-07
• Launch MSRP: $1387 vs $57
• Multiplier Unlocked: true vs false
• Part Number: SREZ5 vs SRNEM