Intel Core i5-2400S vs Intel Core i5-5257U Comparison

The data shows a clear split between the Intel Core i5-5257U and the Intel Core i5-2400S. The older desktop chip, the i5-2400S, dominates traditional multi-core rendering tests, while the newer mobile chip, the i5-5257U, wins decisively in single-core Geekbench performance. Despite the i5-5257U having fewer physical cores, its modern architecture gives it a 55.5% lead in Geekbench single-core, a gap large enough to offset its multi-core deficit in that specific benchmark. The overall average benchmark scores are nearly identical, with the i5-5257U at 976 and the i5-2400S at 968, placing both in the 26th percentile of all CPUs.

The Verdict

The Intel Core i5-2400S is the pick for sustained multi-threaded workloads. It wins five of the seven head-to-head tests, with a consistent margin of approximately 7.5-7.8% across all Cinebench R15, R20, and R23 runs. Its four physical cores provide a structural advantage that its older Sandy Bridge architecture does not squander. The i5-5257U, on the other hand, is the choice for single-threaded responsiveness and tasks that favor newer instruction sets. Its 55.5% lead in Geekbench single-core is the single largest performance gap in the comparison. However, this victory is isolated; it only manages one other win, a 3.7% margin in Geekbench multi-core. For users prioritizing raw rendering throughput, the i5-2400S is the clear winner. For those needing peak single-core speed, the i5-5257U is the only option, though its overall benchmark profile suggests it is not a universally faster chip.

Architecture Differences

The two processors represent distinct eras of Intel design. The i5-5257U is built on the 14 nm Broadwell architecture, while the i5-2400S uses the 32 nm Sandy Bridge process. This process advantage is significant: the i5-5257U packs 1,900 million transistors into a 133 mm² die, whereas the i5-2400S contains 1,160 million transistors on a much larger 216 mm² die. The i5-5257U achieves higher density and efficiency, reflected in its 28 W TDP compared to the i5-2400S's 65 W TDP. The i5-5257U is a dual-core part with four threads, while the i5-2400S is a quad-core part with four threads, meaning the i5-2400S does not use hyper-threading, matching its rival's thread count.

Cache configurations differ substantially. The i5-5257U has 3 MB of shared L3 cache, while the i5-2400S offers double that at 6 MB. Both share the same L1 and L2 cache sizes per core. The i5-5257U features integrated Intel Iris 6100 graphics, a more capable GPU than the i5-2400S's Intel HD 2000. Memory support is limited to DDR3 for both, with dual-channel buses, but the i5-5257U has a specified memory bandwidth of 29.9 GB/s, while the i5-2400S does not list a bandwidth figure. The i5-5257U uses a Gen 2 PCIe interface with 12 lanes, whereas the i5-2400S supports Gen 3 with 16 lanes. The i5-5257U targets the mobile segment on the Intel BGA 1168 socket, while the i5-2400S is a desktop part for Intel Socket 1155.

Head-to-Head Benchmarks

The i5-2400S wins every Cinebench test, which are heavily multi-threaded. In Cinebench R15 multi-core, it scores 262 against the i5-5257U's 242, a delta of -7.6%. The pattern repeats in Cinebench R20 multi-core (1092 vs 1010, -7.5%) and Cinebench R23 multi-core (2601 vs 2406, -7.5%). Even in single-core Cinebench tests, the i5-2400S maintains its lead, scoring 154 in R20 single-core versus 142 (-7.8%) and 367 in R23 single-core versus 339 (-7.6%). This consistent 7.5-7.8% advantage across all Cinebench variants indicates that the i5-2400S's extra cores and larger cache provide a stable performance edge for CPU-bound rendering tasks, regardless of the specific benchmark iteration.

The i5-5257U's wins are concentrated in Geekbench. Its Geekbench single-core score of 922 crushes the i5-2400S's 593, a massive 55.5% delta. This is not a marginal victory; it is a generational leap in per-core efficiency. The i5-5257U also edges out a win in Geekbench multi-core, scoring 1773 against 1709, a 3.7% margin. This multi-core win is notable because the i5-5257U has only two physical cores, yet it still outperforms the four-core i5-2400S in this specific test. The Geekbench suite appears to favor the newer Broadwell architecture's features and memory subsystem, while Cinebench leans on raw core count and raw throughput, where the i5-2400S excels.

Specification Differences

The core difference is the core count and process node. The i5-5257U has 2 cores and 4 threads, while the i5-2400S has 4 cores and 4 threads. The i5-5257U's base clock is 2.70 GHz with a boost of 3.10 GHz, while the i5-2400S runs at 2.50 GHz base and 3.30 GHz boost. The i5-5257U has a lower TDP of 28 W versus the i5-2400S's 65 W. The cache sizes differ: the i5-5257U has 3 MB of L3, the i5-2400S has 6 MB. The i5-5257U is built on a 14 nm process with 1,900 million transistors and a 133 mm² die; the i5-2400S uses a 32 nm process with 1,160 million transistors and a 216 mm² die. The integrated graphics differ (Iris 6100 vs HD 2000). The i5-5257U supports Gen 2 PCIe with 12 lanes; the i5-2400S supports Gen 3 PCIe with 16 lanes. The memory bandwidth is listed for the i5-5257U at 29.9 GB/s but is not provided for the i5-2400S. The sockets and market segments are entirely different: BGA 1168 for mobile versus Socket 1155 for desktop. The i5-5257U has a launch MSRP of $315. The i5-2400S does not have a listed launch MSRP. Both are end-of-life products.

FAQ

Q: Which processor is faster in Cinebench R23 multi-core?

A: The Intel Core i5-2400S is faster, scoring 2601 versus 2406 for the i5-5257U, a delta of -7.5%.

Q: How much better is the i5-5257U in Geekbench single-core?

A: The i5-5257U scores 922, which is 55.5% higher than the i5-2400S's score of 593.

Q: Do both processors have the same number of threads?

A: Yes, both have 4 threads. The i5-5257U has 2 cores with 4 threads, and the i5-2400S has 4 cores with 4 threads.

Q: Which CPU has a larger L3 cache?

A: The i5-2400S has a 6 MB shared L3 cache, double the 3 MB shared L3 cache of the i5-5257U.

Q: What is the TDP difference between the two?

A: The i5-5257U has a 28 W TDP, while the i5-2400S has a 65 W TDP, making the i5-5257U significantly more power-efficient.

Q: Which chip supports newer PCIe technology?

A: The i5-2400S supports Gen 3 PCIe with 16 lanes, while the i5-5257U only supports Gen 2 with 12 lanes.

Where Each One Wins

The Intel Core i5-2400S is the winner for multi-threaded productivity. It wins all four Cinebench multi-core tests, with margins of 7.5-7.6% over the i5-5257U. This makes it the better choice for video rendering, 3D modeling, and any workload that scales with physical core count. Its 6 MB of L3 cache also provides a buffer for data-heavy tasks. The i5-2400S also wins all Cinebench single-core tests, albeit by smaller margins of 7.6-7.8%, which suggests that even in lighter single-threaded tasks, its higher boost clock of 3.30 GHz and larger cache give it a slight edge in Cinebench's specific workload.

The Intel Core i5-5257U wins where single-thread performance is king. Its 55.5% lead in Geekbench single-core is the most pronounced difference in the entire comparison. This indicates superior per-core instruction efficiency, which translates to snappier application launches and better performance in lightly-threaded software that relies on a single strong core. Its 3.7% win in Geekbench multi-core is more surprising, showing that its architectural efficiency can overcome a two-core deficit in certain benchmark suites. Additionally, its integrated Iris 6100 graphics are a clear step above the i5-2400S's HD 2000, making it the better option for systems relying on integrated graphics for basic visual tasks. The i5-5257U also consumes less than half the power of the i5-2400S (28 W vs 65 W), making it ideal for compact or mobile systems where heat and battery life are priorities.