Intel Core i3-5157U vs Intel Core i7-3540M Comparison

The data presents a clear split between two older mobile processors: the Intel Core i3-5157U and the Intel Core i7-3540M. While both are dual-core parts with four threads, they represent different design philosophies and eras. The i7-3540M dominates in all Cinebench tests, while the i3-5157U counters with decisive wins in Geekbench. This is not a simple generational upgrade; it is a trade-off between raw sustained compute and efficiency-oriented architecture.

The Verdict

Based strictly on benchmark results, the Intel Core i7-3540M is the stronger choice for multi-threaded rendering workloads. It wins five of the seven head-to-head comparisons, taking every single Cinebench test. Its lead is consistent, ranging from a 12.6% advantage in Cinebench R15 multi-core and R23 single-core to a 12.8% edge in Cinebench R20 multi-core, R20 single-core, and R23 multi-core. For users running CPU-intensive tasks like video encoding or 3D rendering, the i7-3540M offers a reliable performance advantage.

Conversely, the Intel Core i3-5157U wins the Geekbench tests decisively, with a 35.2% lead in multi-core and a 37.7% lead in single-core. This suggests that for workloads that stress memory latency, integer operations, or specific instruction sets, the newer Broadwell architecture provides a significant edge. The i3-5157U is the better pick for general productivity tasks and applications that favor its architecture, despite its lower clock speeds.

The overall average benchmark scores are nearly identical: 877 for the i3-5157U versus 867 for the i7-3540M. Both processors sit at the 23rd percentile among all CPUs. This means that on average, they perform similarly, but the distribution of their wins is starkly different. The i7-3540M is the specialist for Cinebench-style workloads, while the i3-5157U is the specialist for Geekbench-style workloads. Your choice should be dictated by the specific benchmark suite that best mirrors your intended use.

Architecture Differences

The two processors come from different Intel architectures and manufacturing nodes. The Intel Core i3-5157U is built on the Broadwell architecture, using a 14 nm process node manufactured by Intel. This is a newer, more refined design compared to the i7-3540M, which uses the older Ivy Bridge architecture and a 22 nm process node. The i3-5157U has a die size of 133 mm² and contains 1,900 million transistors, while the i7-3540M has a smaller die size of 118 mm².

The most significant architectural difference lies in the cache hierarchy. The i7-3540M has a larger L3 cache of 4 MB (shared), while the i3-5157U has only 3 MB (shared). Both share the same L1 cache at 64 KB per core and L2 cache at 256 KB per core. Interestingly, despite having a smaller cache, the i3-5157U achieves higher Geekbench scores, suggesting that its Broadwell architecture is more efficient at utilizing cache and memory.

The integrated graphics also differ. The i3-5157U features the Intel Iris 6100, while the i7-3540M has the older Intel HD 4000. While no specific graphics benchmarks are in the data, this indicates a significant generational leap in GPU capability for the i3-5157U. The i3-5157U also supports PCIe Gen 2 with 12 lanes (CPU only), while the i7-3540M has no PCIe information listed. Memory support is identical in type (DDR3) and bus (Dual-channel), but the i3-5157U has a listed memory bandwidth of 29.9 GB/s, while the i7-3540M has no bandwidth figure provided.

Where Each One Wins

The Intel Core i7-3540M wins in all Cinebench tests, which are designed to stress multi-core and single-core rendering performance. Its 3.00 GHz base clock and 3.70 GHz boost clock provide a substantial frequency advantage over the i3-5157U's fixed 2.50 GHz clock. This higher clock speed, combined with the larger 4 MB L3 cache, allows it to sustain higher throughput in compute-intensive tasks. The i7-3540M also carries the "i7" brand, indicating it was positioned as a higher-tier part in its generation.

The Intel Core i3-5157U wins in Geekbench, which is a more general-purpose benchmark that tests a wider range of system scenarios, including memory and integer performance. Its 14 nm process node and Broadwell architecture provide better instructions per clock (IPC) efficiency. Even with a lower clock speed and smaller cache, it outperforms the i7-3540M by over 35% in Geekbench multi-core and nearly 38% in single-core. This suggests the i3-5157U is better suited for everyday applications, web browsing, and office productivity where its architectural efficiency shines. The i3-5157U also has a lower TDP of 28W compared to the i7-3540M's 35W, making it a more power-efficient option for thin-and-light laptops.

FAQ

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

A: The Intel Core i7-3540M is faster. It wins all Cinebench multi-core tests, including a 12.6% lead in R15 (254 vs 222) and a 12.8% lead in R23 (2525 vs 2203).

Q: Why does the i3-5157U win Geekbench despite being an i3?

A: The i3-5157U uses the newer 14 nm Broadwell architecture, which offers better per-clock efficiency than the older 22 nm Ivy Bridge architecture in the i7-3540M. This architectural advantage leads to a 35.2% lead in Geekbench multi-core and a 37.7% lead in single-core.

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

A: Yes, both have 2 cores and 4 threads. They are both dual-core processors with Hyper-Threading.

Q: Which processor has a larger L3 cache?

A: The Intel Core i7-3540M has a larger L3 cache with 4 MB shared, while the Intel Core i3-5157U has 3 MB shared.

Q: Are these processors similar in overall performance?

A: Yes, their average benchmark scores are very close. The i3-5157U has an average score of 877, while the i7-3540M has an average score of 867. Both sit at the 23rd percentile of all CPUs.

Q: Which processor has a lower power draw?

A: The Intel Core i3-5157U has a lower TDP of 28W, while the Intel Core i7-3540M has a TDP of 35W.

Head-to-Head Benchmarks

The head-to-head data reveals a consistent pattern of wins for the i7-3540M in Cinebench. In Cinebench R15 multi-core, the i7-3540M scores 254 against the i3-5157U's 222, a delta of -12.6%. This advantage is maintained in Cinebench R20 multi-core, where the i7-3540M scores 1060 versus 925, a -12.7% difference. The single-core Cinebench tests follow the same trend: R20 single-core shows a -12.8% delta (149 vs 130), and R23 single-core shows a -12.6% delta (356 vs 311). The largest Cinebench win for the i7-3540M is in R23 multi-core, where it scores 2525 against 2203, also a -12.8% difference. This consistency across all Cinebench versions indicates a stable performance gap in favor of the i7-3540M.

The i3-5157U's wins come exclusively in Geekbench, and they are dramatic. In Geekbench multi-core, the i3-5157U scores 1568 against the i7-3540M's 1160, a 35.2% advantage. The single-core Geekbench test shows an even larger gap: 778 for the i3-5157U versus 565 for the i7-3540M, a 37.7% difference. These are substantial margins, suggesting that the i3-5157U's architecture is fundamentally better at handling the types of workloads Geekbench measures. The i3-5157U wins 2 of the 7 benchmarks, while the i7-3540M wins 5.

Specification Differences

The key differences in specifications between the two processors are as follows:

• Clock Speed: The i7-3540M has a base clock of 3.00 GHz and a boost clock of 3.70 GHz. The i3-5157U has a base clock of 2.50 GHz and no boost clock.
• Process Node: The i3-5157U uses a 14 nm process, while the i7-3540M uses a 22 nm process.
• L3 Cache: The i7-3540M has 4 MB shared L3 cache, while the i3-5157U has 3 MB shared L3 cache.
• TDP: The i3-5157U has a TDP of 28W, while the i7-3540M has a TDP of 35W.
• Socket: The i3-5157U uses Intel BGA 1168, while the i7-3540M uses Intel Socket G2 (988B).
• Integrated Graphics: The i3-5157U has Intel Iris 6100, while the i7-3540M has Intel HD 4000.
• Memory Bandwidth: The i3-5157U has a listed memory bandwidth of 29.9 GB/s, while the i7-3540M has no figure listed.
• PCIe: The i3-5157U supports PCIe Gen 2, 12 Lanes (CPU only), while the i7-3540M has no PCIe information.
• Release Date: The i3-5157U was released on 2015-02-28, while the i7-3540M was released on 2013-01-07.
• Launch MSRP: The i3-5157U has a launch MSRP of $315. The i7-3540M has no MSRP listed.