CPU Comparison

Intel Core i3-5157U and Intel Atom C5315 occupy the same percentile tier (23rd) and nearly identical average benchmark scores (877 vs 871), yet they are fundamentally different processors. The Core i3-5157U is a 2015 mobile chip from the Broadwell-U family, while the Atom C5315 is a 2022 server/workstation part from Parker Ridge. Benchmark data shows the Atom C5315 wins all five head-to-head tests, but the real story is how each chip serves a completely different purpose based on its architecture and platform features.

Where Each One Wins

The Intel Atom C5315 wins every single benchmark in the comparison suite, but the margins are consistent and modest rather than dramatic. In Cinebench R15 multicore, the Atom scores 255 versus 222 for the Core i3, a 12.9% advantage. The gap stays nearly identical across all tests: 13% in Cinebench R20 multicore (1063 vs 925), 12.8% in R20 singlecore (149 vs 130), 13% in R23 multicore (2533 vs 2203), and 12.9% in R23 singlecore (357 vs 311). This uniform ~13% lead indicates the Atom's advantage comes from its newer architecture and higher core count, not from any single workload specialization.

The Intel Core i3-5157U has no benchmark wins in this comparison, but its value lies elsewhere. It is the only one of the two with integrated graphics (Intel Iris 6100), making it functional as a complete mobile platform without a discrete GPU. The data shows its Geekbench scores of 1568 multicore and 778 singlecore, which are not available for the Atom, suggesting the Core i3 can handle general-purpose computing tasks in a laptop context. For users who need a compact, low-power mobile processor with graphics output, the Core i3-5157U is the only viable choice here.

Architecture Differences

The two chips come from opposite ends of Intel's design philosophy. The Core i3-5157U uses the Broadwell architecture on a 14 nm process node, with 1,900 million transistors packed into a 133 mm² die. It has 2 cores and 4 threads, with a base clock of 2.50 GHz and no boost clock. Cache is organized as 64 KB L1 per core, 256 KB L2 per core, and 3 MB shared L3. Memory support is DDR3 with dual-channel access and 29.9 GB/s bandwidth. It uses PCIe Gen 2 with 12 lanes and comes with Intel Iris 6100 integrated graphics.

The Atom C5315 uses the Tremont architecture (codename Parker Ridge) on a 10 nm process node, though transistor count and die size are not listed. It has 4 cores and 4 threads, meaning no hyperthreading, with a base clock of 2.40 GHz. Cache differs significantly: 64 KB L1 per core, but 4.5 MB L2 per module, with no L3 cache at all. It supports DDR4 memory in dual-channel configuration with 38.4 GB/s bandwidth, and uses PCIe Gen 3 with 8 lanes. There is no integrated graphics. The Atom supports ECC memory, which the Core i3 does not.

The process node difference (10 nm vs 14 nm) explains why the Atom achieves higher performance despite having a similar clock speed. The newer Tremont architecture is more efficient per clock, and the extra two physical cores provide a 12-13% multicore advantage. However, the Atom's lack of L3 cache and reliance on large L2 modules suggests it is designed for workloads that fit within those modules, rather than large shared data sets.

The Verdict

The Intel Atom C5315 is the better performer in raw compute, winning all five head-to-head benchmarks with a consistent ~13% lead. Its 4 cores, ECC memory support, DDR4 bandwidth of 38.4 GB/s, and PCIe Gen 3 connectivity make it appropriate for server or workstation roles where reliability and memory integrity matter. The data shows it is actively produced, while the Core i3-5157U is end-of-life.

The Intel Core i3-5157U is the choice for mobile computing where integrated graphics are required. Its Intel Iris 6100 GPU eliminates the need for a separate graphics card, which is essential for laptops. The 28 W TDP (versus 38 W for the Atom) also makes it easier to cool in a thin chassis. However, its older DDR3 memory, PCIe Gen 2, and lack of ECC support limit its usefulness in modern server environments.

Users who need a low-cost server processor with ECC memory and decent single-thread performance should pick the Atom C5315. Users who need a complete mobile solution with graphics output and lower power draw should pick the Core i3-5157U, accepting its lower benchmark scores. The data does not support using the Core i3 for compute-intensive server tasks, nor does it support using the Atom for any graphics-related workload.

FAQ

Q: Which processor has better multicore performance?

A: The Intel Atom C5315 wins all multicore tests. In Cinebench R23 multicore, it scores 2533 versus 2203 for the Core i3-5157U, a 13% advantage. The same margin appears in R20 (1063 vs 925) and R15 (255 vs 222).

Q: Does the Intel Atom C5315 support ECC memory?

A: Yes, the Atom C5315 supports ECC memory. The Intel Core i3-5157U does not. This makes the Atom suitable for server applications where memory error correction is critical.

Q: Which processor has integrated graphics?

A: Only the Intel Core i3-5157U has integrated graphics, specifically Intel Iris 6100. The Atom C5315 has no integrated graphics (listed as N/A), requiring a discrete GPU for display output.

Q: How do their single-core scores compare?

A: The Atom C5315 leads in both single-core tests. In Cinebench R23 singlecore, it scores 357 versus 311 for the Core i3, a 12.9% lead. In R20 singlecore, the scores are 149 versus 130, a 12.8% advantage.

Q: What are the memory bandwidth differences?

A: The Atom C5315 supports DDR4 with 38.4 GB/s bandwidth, while the Core i3-5157U supports DDR3 with 29.9 GB/s. The Atom's bandwidth is approximately 28% higher, but this is not directly tested in the benchmark suite.

Q: Which processor has more cores?

A: The Atom C5315 has 4 cores and 4 threads. The Core i3-5157U has 2 cores and 4 threads. Despite having the same thread count on the Core i3 (due to hyperthreading), the Atom wins multicore tests by 12-13%.

Head-to-Head Benchmarks

The Intel Atom C5315 dominates every benchmark in this comparison, but the margins are surprisingly uniform. In Cinebench R15 multicore, the Atom scores 255 against the Core i3's 222, a 12.9% difference. This pattern repeats in Cinebench R20 multicore with scores of 1063 and 925, a 13% gap. The consistency suggests the performance difference is architectural rather than workload-dependent.

Single-core results tell the same story. In Cinebench R20 singlecore, the Atom scores 149 versus 130 for the Core i3, a 12.8% lead. In Cinebench R23 singlecore, the Atom scores 357 versus 311, a 12.9% advantage. This ~13% single-core margin is notable because both chips have similar base clocks (2.40 GHz vs 2.50 GHz). The Atom's newer Tremont architecture on 10 nm clearly extracts more instructions per clock than Broadwell on 14 nm.

The largest absolute difference is in Cinebench R23 multicore, where the Atom leads by 330 points (2533 vs 2203). This test is the most demanding in the suite and shows the Atom's 4 physical cores providing a real advantage over the Core i3's 2 cores with hyperthreading. The Core i3's 4 threads cannot fully compensate for having half the physical cores.

Interestingly, the Core i3-5157U has Geekbench scores (1568 multicore, 778 singlecore) that are not available for the Atom. This means the Core i3 has been tested in general-purpose computing contexts, while the Atom's benchmark data is limited to Cinebench workloads. Users comparing these chips should note that the Geekbench results cannot be directly compared between the two.

Specification Differences

The most significant specification differences between these processors go beyond raw performance. The Core i3-5157U uses the Broadwell architecture on a 14 nm process, while the Atom C5315 uses Tremont on 10 nm. The Core i3 has 1,900 million transistors on a 133 mm² die; the Atom's transistor count and die size are not listed.

Core and thread counts differ: the Core i3 has 2 cores and 4 threads, while the Atom has 4 cores and 4 threads. Base clocks are close (2.50 GHz vs 2.40 GHz), and neither has a boost clock. TDP differs by 10 W, with the Core i3 at 28 W and the Atom at 38 W.

Cache hierarchy is fundamentally different. The Core i3 has 256 KB L2 per core and 3 MB shared L3. The Atom has 4.5 MB L2 per module and no L3 cache. Both have 64 KB L1 per core.

Memory support diverges: the Core i3 uses DDR3, while the Atom uses DDR4. Both are dual-channel, but the Atom's bandwidth is 38.4 GB/s versus 29.9 GB/s. The Atom supports ECC memory; the Core i3 does not.

PCIe connectivity differs: the Core i3 uses Gen 2 with 12 lanes, while the Atom uses Gen 3 with 8 lanes. The Core i3 has Intel Iris 6100 integrated graphics; the Atom has none. The Core i3 uses socket Intel BGA 1168, while the Atom uses Intel BGA 2106.

Production status and release dates also differ. The Core i3 was released on 2015-02-28 and is end-of-life. The Atom was released on 2022-06-05 and is active. The Core i3's launch MSRP was $315; the Atom's was $213. Part numbers are SR26M for the Core i3 and SRL3Y for the Atom. Neither processor has an unlocked multiplier.