Intel Core i3-5157U vs Intel Core i5-5300U Comparison

Head-to-Head Benchmarks

The recorded data presents a surprisingly consistent picture across most Cinebench tests, with the Intel Core i5-5300U taking six of seven head-to-head wins against the Intel Core i3-5157U. The margins are narrow in every case, which raises the question of whether the i5-5300U simply has a better optimized design or if the i3-5157U is held back by its lack of a boost clock.

In multicore workloads, the i5-5300U leads by a small but repeatable margin. The Cinebench R15 multicore score shows the i5-5300U at 230 against the i3-5157U's 222, a delta of -3.5 percent. Cinebench R20 multicore repeats the pattern: 960 for the i5-5300U versus 925 for the i3-5157U, a -3.6 percent difference. Cinebench R23 multicore follows with 2287 versus 2203, again a -3.7 percent edge for the i5-5300U. The consistency across R15, R20, and R23 suggests the i5-5300U's advantage is structural, not workload-specific.

Single-core Cinebench results tell the same story. The i5-5300U scores 135 in Cinebench R20 single-core to the i3-5157U's 130, a -3.7 percent difference. In Cinebench R23 single-core, the i5-5300U posts 322 versus 311, a -3.4 percent lead. These are small margins, but they align perfectly with the multicore deltas, implying the i5-5300U's per-thread performance is consistently stronger.

The one exception is Geekbench multicore, where the i3-5157U actually wins. Here the i3-5157U scores 1568 against the i5-5300U's 1540, a 1.8 percent advantage for the i3. This result breaks the pattern, indicating that the i3-5157U can outperform the i5-5300U in certain synthetic workloads. Meanwhile, Geekbench single-core still favors the i5-5300U: 791 versus 778, a -1.6 percent difference for the i3.

What does this divergence imply? The i5-5300U dominates in Cinebench, which tends to stress sustained multi-threaded and single-threaded compute. The i3-5157U's Geekbench multicore win suggests it can marshal its resources effectively in memory-sensitive scenarios, possibly aided by its higher memory bandwidth of 29.9 GB/s compared to the i5-5300U's 25.6 GB/s. Yet in raw compute tests, the i5-5300U's boost clock of 2.90 GHz versus the i3's fixed 2.50 GHz likely explains its consistent edge.

FAQ

Q: Which CPU wins more benchmark tests in the head-to-head data?

A: The Intel Core i5-5300U wins six of the seven recorded head-to-head benchmarks. The Intel Core i3-5157U wins only Geekbench multicore, with a score of 1568 versus 1540.

Q: How large is the i5-5300U's multicore advantage in Cinebench?

A: The i5-5300U leads by 3.5 to 3.7 percent across Cinebench R15, R20, and R23 multicore tests. For example, R23 multicore shows 2287 for the i5-5300U versus 2203 for the i3-5157U.

Q: Is the i3-5157U competitive in any workload?

A: Yes, the i3-5157U wins Geekbench multicore by 1.8 percent, scoring 1568 against the i5-5300U's 1540. This represents its only head-to-head victory, but it shows the i3 can beat the i5 in certain memory-oriented synthetic tests.

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

A: Yes, both have 2 cores and 4 threads. They also share the same 3 MB shared L3 cache and 64 KB per-core L1 and 256 KB per-core L2 caches.

Q: What is the average benchmark score difference?

A: The i5-5300U has an average benchmark score of 895, while the i3-5157U averages 877. The i5-5300U also sits at the 24th percentile of all CPUs, one point higher than the i3-5157U's 23rd percentile.

Q: Do the two processors share the same architecture and release date?

A: Yes, both are Broadwell-U parts on the 14 nm process, released on the same date, 2015-02-28. Both are end-of-life mobile processors.

The Verdict

The data points to a clear overall winner: the Intel Core i5-5300U. It wins the majority of benchmark tests, holds a higher average benchmark score of 895 versus 877, and reaches the 24th percentile of all CPUs compared to the i3-5157U's 23rd. The i5-5300U's consistent 3.4 to 3.7 percent lead across Cinebench tests, plus its single-core wins in Geekbench, make it the stronger choice for compute-heavy tasks.

However, the i3-5157U is not without merit. Its Geekbench multicore win by 1.8 percent indicates that in certain mixed workloads, particularly those sensitive to memory bandwidth, the i3-5157U can outperform the i5-5300U. The i3-5157U also offers higher memory bandwidth at 29.9 GB/s, which may prove beneficial in data-intensive applications that are not purely CPU-bound.

For a user prioritizing raw CPU compute, the i5-5300U is the logical pick. For a scenario where the i3-5157U's memory bandwidth advantage matters more than Cinebench-style throughput, the i3 could be justified, but the benchmark evidence is heavily tilted toward the i5-5300U.

Specification Differences

The two processors differ in several key specifications despite sharing the same socket, architecture, and release date. The i5-5300U has a lower base clock of 2.30 GHz but includes a boost clock of 2.90 GHz, while the i3-5157U has a higher fixed base clock of 2.50 GHz with no boost capability. Thermal design power differs notably: the i3-5157U is rated at 28 W, while the i5-5300U is rated at 15 W, making the i5 more power-efficient on paper.

Memory bandwidth also differs, with the i3-5157U supporting 29.9 GB/s compared to the i5-5300U's 25.6 GB/s. The integrated graphics are different as well: the i3-5157U features Intel Iris 6100, while the i5-5300U has Intel HD 5500. Transistor counts and die sizes diverge: the i3-5157U has 1,900 million transistors on a 133 mm² die, whereas the i5-5300U has 1,300 million transistors on an 82 mm² die. Part numbers also differ: SR26M for the i3 and SR23X for the i5. Both carry the same launch MSRP of $315.

Architecture Differences

Both CPUs are built on Intel's Broadwell architecture and the Broadwell-U codename, manufactured on Intel's 14 nm process. They share the same 2-core, 4-thread configuration and identical cache hierarchies: 64 KB L1 per core, 256 KB L2 per core, and 3 MB shared L3. Neither supports ECC memory, both use dual-channel DDR3, and both have PCIe Gen 2 with 12 lanes (CPU only).

The architectural differences are subtle. The i5-5300U's boost clock is the most significant functional difference, allowing it to reach 2.90 GHz under load, while the i3-5157U remains locked at 2.50 GHz. The i3-5157U's larger transistor count and die size suggest a more complex implementation, possibly related to its Iris 6100 graphics and higher memory bandwidth, but the benchmark data shows this does not translate into superior compute performance. Both are end-of-life mobile processors, and neither has an unlocked multiplier.

Where Each One Wins

The Intel Core i5-5300U wins in sustained compute benchmarks across the board. It takes Cinebench R15 multicore, R20 multicore, R20 single-core, R23 multicore, and R23 single-core, with deltas ranging from -3.4 to -3.7 percent. It also wins Geekbench single-core with a score of 791 versus 778. For tasks like video rendering, 3D modeling, or any workload that relies on Cinebench-style CPU throughput, the i5-5300U is clearly superior, despite its lower base clock.

The Intel Core i3-5157U wins only Geekbench multicore, scoring 1568 against the i5-5300U's 1540. This suggests the i3-5157U's higher memory bandwidth of 29.9 GB/s can provide a measurable benefit in workloads that are memory-latency or bandwidth-sensitive, even if general compute performance lags. The i3-5157U also offers the Intel Iris 6100 integrated graphics, which may be preferable for light graphics tasks, though no benchmark data in the database directly measures iGPU performance.

In practical terms, the i5-5300U is the better choice for conventional productivity and creative software that scales with CPU compute. The i3-5157U's niche is narrower, but its Geekbench multicore win and higher memory bandwidth indicate it can hold its own in specific scenarios where memory throughput matters more than raw core execution. Both processors sit near the bottom of the overall CPU percentile rankings, at 23rd and 24th, so neither is positioned as a high-end performer in the broader market.