Intel Core i5-2400S vs Intel Core i7-875K Comparison

Where Each One Wins

The benchmark split between these two desktop processors is remarkably clean, with each part claiming victory in a distinct category. The Intel Core i7-875K takes the majority of the recorded tests, winning 5 out of 7 head-to-head matchups, while the Intel Core i5-2400S secures 2 wins. However, the margin of victory tells a more nuanced story than the raw win count.

The i7-875K dominates the Cinebench suite across the board. In Cinebench R15 multicore, it scores 275 against 262 for the i5-2400S, a 5% advantage. That pattern repeats in Cinebench R20 multicore (1146 vs 1092, a 4.9% lead) and Cinebench R23 multicore (2729 vs 2601, also 4.9% ahead). Even in single-threaded Cinebench tests, the older Nehalem part edges ahead: 161 vs 154 in R20 singlecore (4.5% lead) and 385 vs 367 in R23 singlecore (4.9% lead). This suggests the i7-875K holds a consistent, if modest, advantage in rendering workloads that respond to its thread count and cache configuration.

The i5-2400S, by contrast, wins decisively in Geekbench. Its singlecore score of 593 crushes the i7-875K's 499, a massive 15.9% gap. The multicore result is closer but still favors the Sandy Bridge part: 1709 vs 1696, a 0.8% edge. These Geekbench results indicate that the newer architecture in the i5-2400S translates to superior performance in integer and floating-point workloads that are less sensitive to thread scaling, particularly in single-threaded scenarios.

The overall database percentiles reflect this split. The i7-875K sits at the 27th percentile among all CPUs, while the i5-2400S lands at the 26th percentile. Their average benchmark scores are similarly close: 984 for the i7-875K and 968 for the i5-2400S. The nearest rivals for each part confirm their peer group positioning, with the i7-875K matching the Intel Core i3-4130T exactly (984 vs 984, 0% delta) and the i5-2400S nearly matching the AMD Ryzen 7 3700U (968 vs 968, 0.1% delta).

Architecture Differences

The two processors come from different architectural generations, and the data reflects those fundamental changes. The i7-875K uses the Nehalem architecture, codenamed Lynnfield, built on a 45 nm process at Intel's foundry. It packs 774 million transistors into a 296 mm² die. The i5-2400S uses the Sandy Bridge architecture, also from Intel, on a more advanced 32 nm process. That newer node allows 1,160 million transistors in a smaller 216 mm² die, a denser and more efficient design.

Core and thread counts differ significantly. The i7-875K offers 4 cores and 8 threads, enabling simultaneous multithreading. The i5-2400S also has 4 cores but only 4 threads, lacking Hyper-Threading. This explains why the i7-875K consistently wins multicore Cinebench tests despite its older architecture: it can process twice as many threads, even if each individual thread runs slightly less efficiently.

Clock speeds favor the i7-875K on paper. Its base clock is 2.93 GHz with a boost clock of 3.60 GHz, compared to 2.50 GHz base and 3.30 GHz boost for the i5-2400S. Yet the Geekbench singlecore result shows the i5-2400S at 593 vs 499 for the i7-875K, a 15.9% gap that cannot be explained by clock speed alone. The Sandy Bridge architecture's improved instruction handling and memory subsystem evidently deliver higher instructions per clock, allowing it to outperform despite lower clocks.

Cache configurations differ as well. Both parts have 64 KB of L1 cache per core and 256 KB of L2 per core. The shared L3 cache, however, is 8 MB on the i7-875K versus 6 MB on the i5-2400S. The larger L3 cache on the older part likely contributes to its Cinebench wins, as rendering workloads benefit from larger working sets held closer to the cores.

Memory support is DDR3 with dual-channel bus on both, but the i7-875K records a memory bandwidth of 21.3 GB/s while the i5-2400S has no bandwidth figure recorded in the database. PCIe support differs: the i7-875K offers Gen 2 with 16 lanes from the CPU, while the i5-2400S provides Gen 3 with 16 lanes. The i5-2400S also includes integrated Intel HD 2000 graphics, while the i7-875K has no integrated graphics listed.

Power characteristics diverge sharply. The i7-875K has a TDP of 95 watts, while the i5-2400S draws only 65 watts. The 32 nm process and reduced feature set of the Sandy Bridge part clearly deliver better performance per watt, evidenced by its 30-watt lower thermal envelope.

The i7-875K has an unlocked multiplier, allowing overclocking, while the i5-2400S is locked. The i7-875K launched at $353 MSRP in May 2010; the i5-2400S has no recorded launch MSRP and arrived in January 2011. Both are end-of-life products, and both target the desktop segment, though they use different sockets: the i7-875K on Intel Socket 1156 and the i5-2400S on Intel Socket 1155.

The Verdict

The data points to a clear use-case split. For multithreaded rendering and content-creation workloads, the Intel Core i7-875K is the stronger choice. Its 8 threads and 8 MB of L3 cache deliver consistent 4.9% to 5% wins across all three Cinebench multicore tests, and it even wins singlecore Cinebench by 4.5% to 4.9%. The unlocked multiplier adds flexibility for users willing to push clocks further, which the recorded benchmarks do not capture but the hardware permits.

For single-threaded performance and general desktop responsiveness, the Intel Core i5-2400S is clearly superior. Its Geekbench singlecore score of 593 versus 499 represents a 15.9% advantage, a decisive margin that reflects the architectural efficiency of Sandy Bridge. The multicore Geekbench result also favors it, albeit narrowly at 0.8%. Its 65-watt TDP also makes it the more power-efficient option for systems where thermal output and electricity consumption matter.

Users who prioritize threaded rendering workloads should select the i7-875K, especially if they can exploit its unlocked multiplier. Users who run applications with light threading, or who value lower power consumption, should select the i5-2400S. The i7-875K's higher average benchmark score (984 vs 968) and higher percentile rank (27 vs 26) indicate marginally better overall performance in the database's aggregate metrics, but the i5-2400S's single-thread dominance is too large to ignore for many real-world desktop tasks.

FAQ

Q: Which processor has more threads?

A: The Intel Core i7-875K has 8 threads, while the Intel Core i5-2400S has 4 threads. Both have 4 cores.

Q: Why does the i7-875K win all Cinebench tests despite being older?

A: The i7-875K benefits from 8 threads versus 4, plus a larger 8 MB L3 cache compared to 6 MB. Its Cinebench multicore wins range from 4.9% to 5%, and even singlecore Cinebench tests favor it by 4.5% to 4.9%.

Q: How large is the Geekbench singlecore gap?

A: The i5-2400S scores 593 versus 499 for the i7-875K, a 15.9% advantage. This is the largest margin in any recorded benchmark between the two.

Q: Do both processors have integrated graphics?

A: No. The i5-2400S includes Intel HD 2000 integrated graphics, while the i7-875K has no integrated graphics listed in the database.

Q: What is the TDP difference?

A: The i7-875K has a 95-watt TDP, while the i5-2400S has a 65-watt TDP, a 30-watt difference favoring the i5-2400S.

Q: Which processor is unlocked for overclocking?

A: The i7-875K has an unlocked multiplier, while the i5-2400S is locked.

Head-to-Head Benchmarks

The head-to-head results reveal a pattern of narrow Cinebench victories for the i7-875K and a single lopsided Geekbench win for the i5-2400S. Starting with Cinebench R15 multicore, the i7-875K posts 275 against 262 for the i5-2400S, a 5% delta. This is the largest Cinebench margin in either direction, and it establishes the template for the rest of the rendering tests.

Cinebench R20 multicore shows the same story with a 1146 to 1092 score, a 4.9% delta. Cinebench R23 multicore follows at 2729 to 2601, again 4.9%. The consistency of these results across different Cinebench versions suggests the i7-875K's thread advantage scales predictably with workload intensity.

Singlecore Cinebench results are closer but still favor the i7-875K. In Cinebench R20 singlecore, the scores are 161 to 154, a 4.5% delta. Cinebench R23 singlecore shows 385 to 367, a 4.9% delta. These wins are notable because the i5-2400S has higher architectural efficiency on paper, yet the i7-875K's higher boost clock of 3.60 GHz versus 3.30 GHz appears to compensate in these specific workloads.

The Geekbench results flip the script. In Geekbench multicore, the i5-2400S wins 1709 to 1696, a 0.8% delta. This is a narrow victory, and interestingly, it contradicts the Cinebench multicore pattern. The i5-2400S's 4 threads manage to edge out the i7-875K's 8 threads in this test, likely due to better per-thread efficiency and the newer Sandy Bridge memory subsystem.

Geekbench singlecore delivers the most dramatic result of the entire comparison. The i5-2400S scores 593 versus 499 for the i7-875K, a 15.9% delta. This is more than three times larger than any other margin in the head-to-head data. The gap suggests that for lightly threaded applications, the i5-2400S is in a different performance class entirely, despite its lower clock speeds.

The aggregate picture shows the i7-875K winning 5 benchmarks with an average delta of 4.9% across its Cinebench victories, while the i5-2400S wins 2 benchmarks with an average delta of 8.35% across its Geekbench victories. The i5-2400S's wins are fewer but more decisive, while the i7-875K's wins are more numerous but clustered tightly around 5%. For users balancing threaded and single-threaded workloads, the choice depends on which performance profile matters more, as the data shows no single part dominating both categories.