Intel Core i3-9350K vs Intel Core i7-4940MX Comparison

# Intel Core i7-4940MX vs Intel Core i3-9350K

The data presents a curious matchup: a 2014 mobile flagship with a $1096 launch MSRP against a 2019 desktop part that launched at $184. The Intel Core i7-4940MX (Haswell, 22 nm, 4 cores/8 threads) carries the extreme-edition pedigree, while the Intel Core i3-9350K (Coffee Lake, 14 nm, 4 cores/4 threads) represents the modern mainstream. Across every head-to-head benchmark, the i3-9350K wins decisively, with deltas hovering around -10.8% — a consistent margin that suggests architectural efficiency rather than a single-test anomaly. The i7-4940MX's average benchmark score of 1886 slightly edges the i3's 1867, but the percentile rankings tell a near-identical story: 43rd vs 42nd percentile among all CPUs. The real question is what these numbers mean when one chip targets mobile workstations and the other targets desktop gaming rigs.

Head-to-Head Benchmarks

The head-to-head results are remarkably uniform. In Cinebench R15 multi-core, the i3-9350K scores 650 against the i7-4940MX's 580, a -10.8% delta. The single-core R15 test shows 91 vs 81, a -11% gap. Moving to Cinebench R20, the multi-core result is 2711 vs 2418 (-10.8%), and single-core is 382 vs 341 (-10.7%). Cinebench R23 follows the identical pattern: multi-core 6456 vs 5759 (-10.8%), single-core 911 vs 813 (-10.8%).

The consistency of these margins is striking. Every single benchmark produces nearly the same percentage difference, regardless of the workload's threading demands. This uniformity suggests the i3-9350K's advantage stems from higher clock speeds rather than core-count efficiency — the i7-4940MX has 8 threads to the i3's 4, yet still loses multi-core tests by the same margin as single-core tests. The i3-9350K boosts to 4.60 GHz against the i7's 4.00 GHz, and its 4.00 GHz base clock exceeds the i7's 3.10 GHz boost clock entirely. The i7-4940MX's hyper-threading compensates for some of the clock deficit but not enough to close the gap. Notably, the i7-4940MX shows zero wins in the head-to-head suite; the i3-9350K claims all six tests.

Where Each One Wins

The i3-9350K wins in every measured workload category. Its Cinebench R23 multi-core score of 6456 places it roughly 12% ahead of the i7-4940MX's 5759, a significant margin for rendering tasks that scale with sustained throughput. Single-core performance tells the same story: 911 vs 813 in R23, indicating the i3 handles lightly-threaded applications like older games or legacy productivity software with proportionally better responsiveness. The i3-9350K's higher TDP of 91W versus 57W likely enables its sustained clock advantage, though the benchmark data doesn't directly measure power efficiency.

The i7-4940MX's case rests on its mobile form factor. As a Socket G3 part in the mobile segment, it delivers 8 threads in a 57W envelope — a capability the i3-9350K cannot match for portable systems. The i7's Geekbench scores (3869 multi-core, 1227 single-core) are the only benchmark results not shared in the head-to-head suite, and they show the chip operating in a different performance tier than its Cinebench numbers suggest. However, in every directly comparable test, the i3-9350K is faster. The i7-4940MX's percentile ranking of 43 vs the i3's 42 is effectively a tie, but the i3 achieves that standing with a far lower launch MSRP of $184 compared to the i7's $1096.

Architecture Differences

The architectural gulf between these two parts spans five years of Intel evolution. The i7-4940MX uses the Haswell architecture on a 22 nm process, while the i3-9350K employs Coffee Lake on 14 nm. The process shrink reduces die size from 177 mm² to 126 mm², and the i7 packs 1,400 million transistors — the i3's transistor count is not listed, but the smaller die suggests a denser, more efficient layout. Both share the same L1 cache (64 KB per core) and L2 cache (256 KB per core), and both have 8 MB of shared L3 cache, so the cache hierarchy is structurally identical.

The memory interface diverges significantly. The i7-4940MX supports DDR3 with dual-channel memory bandwidth of 25.6 GB/s, while the i3-9350K supports DDR4 at 38.4 GB/s — a 50% bandwidth advantage that likely contributes to the i3's consistent benchmark lead. The i7 also lacks ECC memory support, while the i3 includes it. Both use PCIe Gen 3 with 16 lanes from the CPU, so expansion capability is equivalent. The integrated graphics differ: Intel HD 4600 on the i7 versus UHD 630 on the i3, though neither is positioned as a gaming solution. The i7's 57W TDP reflects its mobile design, while the i3's 91W TDP indicates desktop power delivery.

Specification Differences

The most obvious difference is thread count: the i7-4940MX has 8 threads from 4 cores, while the i3-9350K has only 4 threads from 4 cores. Clock speeds favor the i3 across the board: 4.00 GHz base vs 3.10 GHz, and 4.60 GHz boost vs 4.00 GHz. The TDP gap is substantial (91W vs 57W), reflecting the i3's desktop power budget versus the i7's mobile efficiency target. Sockets differ entirely: Socket 1151 for the i3, Socket G3 for the i7. Memory support splits along generational lines — DDR4 vs DDR3 — with bandwidth of 38.4 GB/s vs 25.6 GB/s. ECC support is present on the i3 but absent on the i7.

The launch MSRP difference is enormous: $1096 for the i7-4940MX versus $184 for the i3-9350K. Both are end-of-life products, and both have unlocked multipliers for overclocking. The i7 was released on 2014-01-19, while the i3 arrived on 2019-04-22. The i7's part number is SR1PP; the i3's is SRCZT. The i7 targets the mobile market segment, the i3 targets desktop. The i7's integrated graphics are HD 4600, the i3's are UHD 630. The i7's die size is 177 mm² with 1,400 million transistors; the i3's die size is 126 mm² with transistors not listed.

FAQ

Q: Which CPU is faster in single-core performance?

A: The Intel Core i3-9350K wins every single-core benchmark. In Cinebench R15, it scores 91 vs 81 (-11%); in R20, 382 vs 341 (-10.7%); in R23, 911 vs 813 (-10.8%). The i3's higher boost clock of 4.60 GHz versus 4.00 GHz drives this advantage.

Q: Does the i7-4940MX's extra threads help in multi-core workloads?

A: Despite having 8 threads versus the i3's 4, the i7-4940MX loses every multi-core test by the same -10.8% margin seen in single-core tests. In Cinebench R23 multi-core, the i3 scores 6456 vs 5759. The thread advantage does not overcome the clock speed and memory bandwidth deficits.

Q: What is the biggest specification difference between these two?

A: The memory interface is the most dramatic gap. The i3-9350K supports DDR4 with 38.4 GB/s bandwidth, while the i7-4940MX supports DDR3 at 25.6 GB/s — a 50% bandwidth advantage for the i3. The i3 also has a 91W TDP versus 57W, and a base clock of 4.00 GHz versus 3.10 GHz.

Q: Are these CPUs comparable for gaming?

A: The benchmark data shows the i3-9350K is faster in all Cinebench tests, which are typical CPU workload indicators. The i3's higher single-core scores (911 vs 813 in R23) suggest better performance in games that rely on single-thread performance. However, the i7-4940MX is a mobile part, while the i3 is desktop-only.

Q: Which CPU has a better architectural efficiency?

A: The i3-9350K demonstrates better efficiency per thread. It matches the i7's 4-core configuration but adds higher clocks and newer DDR4 memory support. The i7's 22 nm Haswell design with 1,400 million transistors on a 177 mm² die is older and less efficient than the i3's 14 nm Coffee Lake design on a 126 mm² die.

Q: Why do the average benchmark scores differ from the head-to-head results?

A: The i7-4940MX has an average benchmark score of 1886 versus the i3's 1867, which seems contradictory to the head-to-head losses. However, the i7's Geekbench scores (3869 multi-core, 1227 single-core) are included in its average but not in the head-to-head suite, which only covers Cinebench tests. The i3 lacks Geekbench results in its data.

The Verdict

The data is unambiguous: the Intel Core i3-9350K is the faster processor in every directly comparable benchmark. The i3 wins all six head-to-head tests with consistent -10.8% deltas, achieves a higher single-core and multi-core Cinebench scores, and does so with a launch MSRP of $184 versus the i7-4940MX's $1096. For any workload measured by Cinebench — rendering, encoding, general CPU throughput — the i3-9350K is the clear choice.

The i7-4940MX's remaining argument is its mobile form factor. It delivers 8 threads in a 57W TDP for Socket G3 laptops, which the i3-9350K cannot match as a 91W desktop part. The i7's Geekbench scores suggest it retains competitive standing in some workloads, and its unlocked multiplier allows overclocking. But the benchmark results indicate that even with overclocking, the i7's older Haswell architecture and DDR3 memory bandwidth would struggle to close the gap against the i3's Coffee Lake design.

Buyers choosing between these two should base their decision on platform requirements rather than raw performance. The data shows the i3-9350K wins on every performance metric measured, making it the superior choice for desktop users. The i7-4940MX only makes sense for those who need a high-thread-count mobile processor with the i7 Extreme branding — and even then, the benchmark results show it would be slower than the i3 in most tasks. The verdict is straightforward: the i3-9350K is the better performer, and the i7-4940MX's only advantage is its portability.