Intel Core i3-8350K vs Intel Core i5-7640X Comparison

Head-to-Head Benchmarks

The benchmark data presents a clean sweep for the Intel Core i5-7640X. Across all eight recorded tests, the i5-7640X finishes ahead of the Intel Core i3-8350K. The most decisive margin appears in Geekbench single-core, where the i5-7640X scores 1736 against the i3-8350K's 1564, a lead of 11%. This is the largest single delta in the entire comparison, suggesting a notable advantage in lightly threaded workloads that depend on peak single-core throughput.

In multi-threaded Cinebench tests, the i5-7640X maintains a consistent but smaller edge. In Cinebench R15 multi-core, it scores 607 versus 593 for the i3-8350K, a delta of 2.4%. That pattern repeats in Cinebench R20 multi-core with 2533 against 2471, a delta of 2.5%, and in Cinebench R23 multi-core with 6031 against 5884, again a delta of 2.5%. The single-core Cinebench results follow the same trend: R15 shows 85 versus 83 (2.4%), R20 shows 357 versus 348 (2.6%), and R23 shows 851 versus 830 (2.5%).

Geekbench multi-core also favors the i5-7640X by 5137 to 4992, a delta of 2.9%. This is a slightly larger multi-core margin than the Cinebench multi-core tests, but still modest. Overall, the i5-7640X wins all eight head-to-head matchups, with deltas ranging from 2.4% to 11%. The average benchmark score for the i5-7640X is 2167, while the i3-8350K sits at 2096, a difference of roughly 3.4% in the aggregate.

The percentile rankings place both chips near the lower-middle of the database. The i5-7640X sits at the 47th percentile of all CPUs, while the i3-8350K is at the 46th percentile. This means that despite the i5-7640X winning every direct comparison, neither processor is positioned as a high performer among the broader field of CPUs in the database. The nearest rivals for the i5-7640X include the Intel Core i5-1145G7E (average score 2174, delta -0.3%), the AMD Ryzen 5 3400GE (2175, -0.3%), the Intel Core i7-5950HQ (2158, 0.4%), and the Intel Core i7-1185GRE (2178, -0.5%). For the i3-8350K, the closest competitors are the AMD Ryzen 7 1700X (2094, 0.1%), the AMD Ryzen 5 PRO 2400G (2101, -0.2%), the AMD Ryzen Embedded R2544 (2086, 0.5%), and the Intel Core i5-8259U (2108, -0.6%). These rival deltas are all within a fraction of a percent, indicating that both reviewed parts land in a tightly clustered performance band.

The Verdict

The data is unambiguous: the Intel Core i5-7640X outperforms the Intel Core i3-8350K in every recorded benchmark. No test in the database shows the i3-8350K ahead. The margin is small in most multi-core workloads, between 2.4% and 2.9%, but the single-core Geekbench gap of 11% gives the i5-7640X a clear edge for applications that rely heavily on single-thread speed.

That said, the i3-8350K is not far behind. Its aggregate benchmark score of 2096 places it within 3.4% of the i5-7640X's 2167. For users comparing these two strictly on measured performance, the i5-7640X is the faster part, but the difference in most workloads is modest. The i3-8350K does offer features that the i5-7640X lacks, such as integrated graphics (UHD Graphics 630) and ECC memory support, which may matter for specific build requirements despite the performance deficit.

The i5-7640X also demands a different platform: it uses Intel Socket 2066, while the i3-8350K uses Intel Socket 1151. The i5-7640X has a higher TDP of 112 watts versus 91 watts for the i3-8350K, and it supports quad-channel memory versus dual-channel on the i3-8350K. The i5-7640X also carries a higher base clock of 3.90 GHz with a boost clock of 4.30 GHz, while the i3-8350K runs at a fixed 4.00 GHz with no boost clock listed. These platform and specification differences may weigh as heavily as raw benchmark scores for a potential buyer.

Strictly from the recorded data, the i5-7640X is the faster processor in every test. The i3-8350K's advantages lie outside performance: it has a lower TDP, a smaller die size, integrated graphics, ECC support, and a launch MSRP of $168. The i5-7640X has no launch MSRP listed in the database. The choice between the two depends on whether the user prioritizes the small but consistent performance lead of the i5-7640X or the platform features and efficiency of the i3-8350K.

Architecture Differences

The two processors come from different Intel architectures. The i5-7640X is built on Kaby Lake, specifically the Kaby Lake-X variant, and is part of the Core i5 X-Series 7th Gen lineup. The i3-8350K uses Coffee Lake and belongs to the Core i3 Coffee Lake generation. Both are fabricated on Intel's 14 nm process node, and both are manufactured by Intel.

Core counts are identical: each has 4 cores and 4 threads, with no hyper-threading on either part. Cache layouts are similar in structure but differ in total L3. The i5-7640X has 64 KB of L1 per core and 256 KB of L2 per core, with 6 MB of shared L3. The i3-8350K also has 64 KB of L1 per core and 256 KB of L2 per core, but its L3 is larger at 8 MB shared. The die size for the i3-8350K is listed as 126 mm², while the i5-7640X has no die size recorded.

Clock behavior differs. The i5-7640X has a base clock of 3.90 GHz and a boost clock of 4.30 GHz. The i3-8350K has a base clock of 4.00 GHz and no boost clock listed, meaning it appears to run at a fixed frequency. Both CPUs have an unlocked multiplier, so overclocking is possible on either part.

Memory support is a major differentiator. The i5-7640X supports quad-channel DDR4, while the i3-8350K supports dual-channel DDR4 with a listed memory bandwidth of 38.4 GB/s. The i3-8350K supports ECC memory, while the i5-7640X does not. PCIe support is Gen 3 on both, but the i3-8350K lists 16 lanes (CPU only), while the i5-7640X simply lists Gen 3 without a lane count.

Integrated graphics are present only on the i3-8350K, which includes UHD Graphics 630. The i5-7640X has no integrated graphics listed. Sockets differ as well: the i5-7640X uses Intel Socket 2066, while the i3-8350K uses Intel Socket 1151. The i3-8350K is marked as end-of-life in production status, while the i5-7640X has no production status recorded. Release dates are close: the i5-7640X was released on 2017-06-25, and the i3-8350K on 2017-10-04. The i3-8350K has a part number of SR3N4; the i5-7640X has none listed.

FAQ

Q: Which CPU is faster in multi-core workloads?

A: The Intel Core i5-7640X wins every multi-core test. In Cinebench R15 multi-core it scores 607 against 593, in R20 it scores 2533 against 2471, in R23 it scores 6031 against 5884, and in Geekbench multi-core it scores 5137 against 4992. Deltas range from 2.4% to 2.9%.

Q: How large is the single-core performance gap?

A: The i5-7640X leads in all single-core tests. The smallest gap is in Cinebench R15 single-core at 85 versus 83 (2.4%), and the largest is in Geekbench single-core at 1736 versus 1564, a delta of 11%.

Q: Do both CPUs have the same number of cores and threads?

A: Yes. Both the Intel Core i5-7640X and the Intel Core i3-8350K have 4 cores and 4 threads. Neither supports additional threads per core.

Q: Does the i3-8350K support ECC memory?

A: Yes, the i3-8350K lists ECC memory support as true. The i5-7640X lists ECC memory support as false.

Q: Which CPU has integrated graphics?

A: Only the Intel Core i3-8350K includes integrated graphics, specifically UHD Graphics 630. The Intel Core i5-7640X has no integrated graphics listed in the database.

Q: How do the two CPUs compare in overall database percentile?

A: The i5-7640X is at the 47th percentile of all CPUs, and the i3-8350K is at the 46th percentile. The average benchmark score for the i5-7640X is 2167, while the i3-8350K averages 2096.

Where Each One Wins

The Intel Core i5-7640X wins every head-to-head benchmark in the database, so on pure measured performance it is the stronger choice across all tested workloads. Its largest advantage is in Geekbench single-core, where the 11% lead suggests it is particularly well suited for applications that depend on fast single-thread execution, such as older games or lightly threaded productivity software. The smaller but consistent multi-core wins, between 2.4% and 2.9%, mean it also holds an edge in fully threaded rendering tasks like Cinebench, though the margin there is less dramatic. For users who want the highest possible scores in the recorded tests, the i5-7640X is the pick.

The i3-8350K does not win any benchmark, but it offers compensating platform features. Its integrated UHD Graphics 630 means it can operate without a discrete graphics card in systems where that is acceptable, a capability the i5-7640X lacks entirely. ECC memory support opens the i3-8350K for environments where data integrity is critical, and its lower TDP of 91 watts makes it a more efficient option in terms of thermal load. The dual-channel memory bus with a listed bandwidth of 38.4 GB/s is narrower than the quad-channel setup of the i5-7640X, but it remains fully adequate for the i3-8350K's platform. The i3-8350K also has a larger L3 cache at 8 MB shared versus 6 MB on the i5-7640X, which can help in cache-sensitive workloads even if the benchmark scores do not reflect a win.

For a system builder prioritizing the absolute top measured performance in this comparison, the Intel Core i5-7640X is the correct choice. For a builder who needs integrated graphics, ECC support, or a lower TDP, the Intel Core i3-8350K is the only one of the two that offers those features, and its performance is close enough that the practical difference in most multi-core tasks is small. The i3-8350K also carries a launch MSRP of $168, while the i5-7640X has no launch MSRP recorded, which may be relevant for purchase decisions. In summary, the data says the i5-7640X is faster; the feature set says the i3-8350K is more versatile for specific use cases.