Intel Core i5-5257U vs Intel Core i7-965 Comparison

Head-to-Head Benchmarks

The benchmark database records five direct comparisons between the Intel Core i5-5257U and the Intel Core i7-965, and the outcome is uniform: the i7-965 wins every single test. That is a clean sweep, with the i5-5257U taking zero wins and the i7-965 taking five. The margin is remarkably consistent across all workloads, hovering near 16.5 percent in every discipline.

Starting with multi-core performance, the Cinebench R15 multicore test shows the i7-965 scoring 290 against the i5-5257U's 242, a delta of 16.6 percent. Moving to Cinebench R20 multicore, the gap widens slightly to 16.7 percent, with scores of 1212 versus 1010. The Cinebench R23 multicore test follows the same pattern: the i7-965 posts 2886 while the i5-5257U manages 2406, again a 16.6 percent deficit for the newer chip.

Single-core results tell the same story. In Cinebench R20 single-core, the i7-965 scores 170 compared to the i5-5257U's 142, a 16.5 percent advantage. The Cinebench R23 single-core test shows 407 for the i7-965 and 339 for the i5-5257U, a 16.7 percent gap. What is striking here is the consistency: whether the test is single-threaded or fully parallel, the older desktop processor leads by essentially the same margin. This suggests the advantage is not merely core count but something fundamental to the architecture.

The i5-5257U does have additional benchmark data in the database that the i7-965 lacks. Geekbench results show the i5-5257U scoring 1773 in multi-core and 922 in single-core, but there are no corresponding Geekbench scores for the i7-965, so a direct comparison there is not possible. The average benchmark score across all recorded tests puts the i7-965 at 993 and the i5-5257U at 976, a narrow 1.7 percent overall difference. This is interesting because the head-to-head Cinebench tests show a much larger gap, but the i5-5257U's Geekbench numbers help pull its average closer.

Looking at the percentile rankings, both processors sit near the bottom of the database. The i5-5257U falls in the 26th percentile of all CPUs, while the i7-965 sits just one percentile higher at 27. In other words, despite the i7-965's consistent head-to-head wins, neither chip is a standout in the broader landscape. The nearest rivals for the i5-5257U include the Intel Core i3-4150T, Intel Core i3-4130, AMD Athlon X4 840, and AMD A10-7870K, all matching its average score of 975 with a delta of just 0.1 percent. The i7-965's nearest rivals are the Intel Core i7-960, AMD Phenom II X6 1065T, and Intel Xeon W3565, all at 993 with zero delta, plus the Intel Core i3-8130U at 994 with a negative 0.1 percent delta.

The Verdict

The data points to a clear conclusion for raw compute performance: the Intel Core i7-965 is the stronger processor. Every recorded head-to-head benchmark shows it ahead by roughly 16.5 to 16.7 percent, and its average benchmark score of 993 edges out the i5-5257U's 976. The i7-965 also holds a slight percentile advantage, ranking in the 27th percentile versus the 26th.

However, the choice depends heavily on context, and the database reveals substantial differences beyond raw scores. The i5-5257U is a mobile processor in the Broadwell-U family, released in early 2015, while the i7-965 is a desktop part from the Nehalem generation, released in late 2008. The i5-5257U has a thermal design power of 28 watts, whereas the i7-965 draws 130 watts. This is not a trivial difference; it means the i7-965 requires a much more substantial cooling solution and power delivery. The i5-5257U also includes integrated Intel Iris 6100 graphics, while the i7-965 has no integrated graphics at all.

For a desktop user who already has a dedicated graphics card and adequate cooling, the i7-965 offers measurably better compute performance across the board. The 16.6 percent advantage in Cinebench R23 multicore, translating to 2886 versus 2406, is meaningful for rendering and multi-threaded workloads. The single-core lead of 16.7 percent in Cinebench R23, 407 versus 339, also benefits lightly threaded applications.

For a mobile user, the i5-5257U is the only viable option given the socket and form factor, but the performance gap is real. The data shows it trails the i7-965 in every comparable test, and its 26th percentile ranking confirms it is not a high-performance part. Still, the 28 watt TDP and integrated graphics make it suitable for compact systems where the i7-965's 130 watt requirement would be prohibitive.

The i7-965 also has an unlocked multiplier, which the i5-5257U lacks. That means the i7-965 can be overclocked, potentially extending its lead further, though the database does not include overclocked results. The i5-5257U's production status is end-of-life, as is the i7-965's, so neither is a current-generation purchase.

Architecture Differences

The two processors come from different eras and different design philosophies. The Intel Core i5-5257U is built on Broadwell, specifically the Broadwell-U codename, using a 14 nanometer process node. The Intel Core i7-965 uses Nehalem, codenamed Bloomfield, on a 45 nanometer process. This is a significant process generation gap: the i5-5257U packs 1,900 million transistors on a die size of 133 mm², while the i7-965 has 731 million transistors on a much larger 263 mm² die. The newer process allows the i5-5257U to fit more transistors into roughly half the silicon area.

The core configurations differ as well. The i5-5257U has 2 cores and 4 threads, while the i7-965 has 4 cores and 8 threads. This is a direct consequence of their market positioning: the i5-5257U is a dual-core mobile part, the i7-965 is a quad-core desktop extreme edition. Cache hierarchies also diverge. Both have 64 KB of L1 cache per core and 256 KB of L2 per core, but the L3 cache is substantially different. The i5-5257U has 3 MB of shared L3 cache, while the i7-965 has 8 MB of shared L3. That larger cache is one reason the i7-965 maintains its lead even in single-core tests.

The memory controller architecture differs too. The i5-5257U supports dual-channel DDR3 memory with a recorded bandwidth of 29.9 GB/s. The i7-965 supports triple-channel DDR3, though the database does not list a bandwidth figure for it. Triple-channel memory access can provide higher bandwidth in memory-intensive workloads, which may contribute to the i7-965's consistent advantage. Neither processor supports ECC memory, and both use PCI Express Gen 2, though the i5-5257U has 12 lanes from the CPU while the i7-965's lane count is not specified.

The integrated graphics situation is a major architectural divergence. The i5-5257U includes Intel Iris 6100 graphics, while the i7-965 has no integrated graphics at all. This reflects their intended uses: the mobile chip must handle display output on its own, while the desktop chip assumes a discrete graphics card. The i5-5257U's socket is Intel BGA 1168, meaning it is soldered to the motherboard, whereas the i7-965 uses Intel Socket 1366, a socketed design that allows for replacement or upgrades.

Specification Differences

Several specifications separate these two processors, and they are worth enumerating directly. The core count differs: 2 cores for the i5-5257U versus 4 cores for the i7-965, and thread counts are 4 versus 8 respectively. Base clock speeds show the i7-965 at 3.20 GHz versus the i5-5257U's 2.70 GHz. Boost clocks also favor the i7-965 at 3.47 GHz versus 3.10 GHz.

Thermal design power is a major differentiator. The i5-5257U is rated at 28 watts, while the i7-965 is rated at 130 watts. That is a 102 watt difference, which affects cooling requirements, power supply needs, and system form factor. The sockets are incompatible: BGA 1168 for the i5-5257U and Socket 1366 for the i7-965.

The market segments differ: the i5-5257U is a mobile processor, the i7-965 is a desktop processor. Their release dates are far apart, with the i5-5257U released in early 2015 and the i7-965 in late 2008. The i5-5257U has a listed launch MSRP of $315, while the i7-965 has no launch MSRP in the database. The multiplier is unlocked on the i7-965 but locked on the i5-5257U. The integrated graphics presence is another difference: the i5-5257U has Intel Iris 6100, the i7-965 has none. Finally, the memory bus differs, with the i5-5257U using dual-channel and the i7-965 using triple-channel, and the i5-5257U has a recorded memory bandwidth of 29.9 GB/s while the i7-965 has no recorded bandwidth.

FAQ

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

A: The Intel Core i7-965 wins every recorded multi-core test. In Cinebench R23 multicore, it scores 2886 versus the i5-5257U's 2406, a 16.6 percent advantage. In Cinebench R20 multicore, the margin is 1212 versus 1010, a 16.7 percent lead.

Q: Does the i5-5257U win any single-core tests?

A: No. The i7-965 leads in both single-core tests recorded. In Cinebench R23 single-core, it scores 407 against 339, a 16.7 percent gap. In Cinebench R20 single-core, it scores 170 against 142, a 16.5 percent margin.

Q: What is the difference in average benchmark scores?

A: The i7-965 has an average benchmark score of 993, while the i5-5257U averages 976. That is a 1.7 percent difference favoring the i7-965, though the head-to-head Cinebench tests show a much larger gap of around 16.6 percent.

Q: How do these processors compare in power consumption?

A: The i5-5257U has a thermal design power of 28 watts, while the i7-965 is rated at 130 watts. This makes the i5-5257U far more suitable for compact or mobile systems, while the i7-965 requires substantial cooling.

Q: Do both processors support the same memory configuration?

A: No. The i5-5257U uses dual-channel DDR3 with a recorded bandwidth of 29.9 GB/s. The i7-965 uses triple-channel DDR3, though no bandwidth figure is recorded for it. Both support DDR3 but with different memory bus architectures.

Q: Which processor has integrated graphics?

A: Only the i5-5257U has integrated graphics, specifically Intel Iris 6100. The i7-965 has no integrated graphics at all, meaning it requires a discrete graphics card for display output.