Intel Celeron 3865U

The Intel Celeron 3865U is a dual-core, dual-thread mobile processor from the Kaby Lake-U family, released in early 2017 and now end-of-life. Its average benchmark score of 432 places it at the 6th percentile of all CPUs in the database, indicating that it sits near the very bottom of the performance spectrum. With a base clock of 1800 MHz and no boost capability, the data reveals a chip designed for basic tasks rather than demanding workloads.

Benchmark Performance

The Celeron 3865U's benchmark results are consistently low across all tested suites. In Cinebench R15 multicore, it scores 114, while in R20 multicore it reaches 475 and in R23 multicore 1131. Single-core results are even more modest: 66 in R20 and 159 in R23. Geekbench shows a similar pattern, with a single-core score of 392 and a multicore score of 689. These numbers align with its 6th percentile ranking—only 6% of all CPUs in the database perform worse.

Relative to its nearest rivals, the Celeron trails by fractions of a percent. Its average score of 432 is 0.1% lower than the AMD Athlon II X3 415e (avgScore 433), 0.5% lower than the AMD A10-4655M (434), and 0.7% lower than both the Intel Xeon E5504 and Intel Core i5-2467M (each 435). These deltas are negligible in real-world terms; the Celeron is effectively at parity with these older or similarly low-end parts. The data suggests that the 3865U is not meaningfully slower than its closest competitors, but it also offers no performance advantage.

The ratio between multicore and single-core scores varies dramatically by benchmark. In Geekbench, multicore is 1.76 times the single-core score (689 vs 392), which is consistent with a two-thread processor achieving near-linear scaling. However, in Cinebench R23, the multicore score is 7.1 times the single-core score (1131 vs 159), a gap that is far too large for a dual-core chip. This discrepancy hints that the Cinebench single-core tests may be particularly sensitive to the Celeron's low clock speed or that the multicore test benefits from some other factor. Regardless, the absolute values remain extremely low.

Who Should Consider It

Given its performance class, the Celeron 3865U is only suitable for light, single-threaded workloads. Office productivity tasks like word processing, spreadsheets, and web browsing might run acceptably, but the low single-core scores—392 in Geekbench and 159 in R23—suggest that even these may feel sluggish with multiple applications open. The 2-core/2-thread configuration limits multitasking; background processes will compete for the same execution resources.

Gaming is not a realistic use case. The integrated Intel HD Graphics 610 provides no discrete GPU, and the CPU's compute scores (e.g., 689 in Geekbench multicore) are far below what modern games require. The data does not include any gaming-specific benchmarks, but the overall percentile ranking makes it clear that this chip is not designed for entertainment beyond basic video playback.

For content creation, the Celeron is equally inadequate. The Cinebench R23 multicore score of 1131 is a fraction of what even entry-level desktop processors achieve, and the lack of boost clock means sustained performance is capped at 1800 MHz. Users who need to render video, compile code, or process large datasets should look elsewhere. The chip's only realistic audience is those running lightweight, single-purpose applications on a low-power, fanless device—though even then, the performance ceiling is very low.

Power and Thermals

The Celeron 3865U has a TDP of 15 watts, a typical figure for ultra-low-voltage mobile processors. This low power envelope means it can be cooled by a simple passive heatsink or a small, low-speed fan. The absence of a boost clock (base clock is 1800 MHz) ensures that power draw remains steady, avoiding thermal spikes. In a thin-and-light laptop or a compact mini-PC, the 15W TDP allows for silent operation and minimal heat dissipation. The 14nm process node from Intel contributes to this efficiency, though the chip's performance is limited by its modest architecture and core count.

How It Compares

AMD Athlon II X3 415e: This three-core desktop processor has an average score of 433, which is 0.1% higher than the Celeron's 432. The performance difference is essentially nonexistent, despite the Athlon having an extra core. The Celeron's newer architecture and higher clock speed (1800 MHz vs the Athlon's unspecified clock) may offset the core count disadvantage in single-threaded tasks, but the data shows no clear winner.

AMD A10-4655M: With an average score of 434, this mobile APU is 0.5% ahead of the Celeron. The A10-4655M also integrates a more capable GPU, but the CPU-side performance is nearly identical. The Celeron's 14nm process gives it a power efficiency edge, but in raw compute, the two are indistinguishable.

Intel Xeon E5504: This server-oriented Xeon scores 435, 0.7% above the Celeron. The Xeon has more cores (though the exact count is not in the data), but its older architecture and lower clock speed likely explain the small margin. The Celeron's advantage in single-thread performance (if any) is not visible in the aggregate score.

Intel Core i5-2467M: Also scoring 435, this older mobile Core i5 is 0.7% faster than the Celeron. The i5-2467M is a dual-core with Hyper-Threading, but the Celeron's higher base clock (1800 MHz vs the i5's unspecified clock) may compensate. The delta is so small that it would be imperceptible in daily use.

Platform and Compatibility

The Celeron 3865U uses the Intel BGA 1356 socket, which means it is soldered to the motherboard and cannot be upgraded. It supports DDR3 and DDR4 memory in a dual-channel configuration, though the exact memory bandwidth is not specified. The CPU provides 10 PCIe Gen 2 lanes, which limits expansion options; a discrete GPU or NVMe drive would be constrained by the older standard. Integrated graphics are handled by Intel HD Graphics 610, which is sufficient for basic display output but not for gaming or GPU-accelerated tasks.

The chip was released on January 2, 2017, with a launch MSRP of $107. It is now end-of-life, meaning no new production is planned. For a system builder, this means sourcing the chip from existing inventory or used markets. The BGA package also implies that the motherboard and CPU are a single unit, so platform longevity is tied to the entire device.

FAQ

Q: Does the Intel Celeron 3865U support ECC memory?

A: No, the FACT PACK lists ECC memory as false.

Q: What is the base clock speed of the Celeron 3865U?

A: The base clock is 1800 MHz, and there is no boost clock.

Q: How many cores and threads does it have?

A: It has 2 cores and 2 threads.

Q: What integrated graphics does it include?

A: It includes Intel HD Graphics 610.

Q: What is the production status?

A: It is marked as end-of-life.

Q: What memory types are supported?

A: It supports DDR3 and DDR4 in a dual-channel configuration.

Single-Thread vs Multi-Thread Behavior

The Celeron 3865U exhibits unusual scaling between single-thread and multi-thread workloads. In Geekbench, the multicore score of 689 is 1.76 times the single-core score of 392—a reasonable figure for a dual-core processor with no Hyper-Threading. This suggests that the two cores are utilized effectively and that the chip can handle parallel tasks without significant contention.

However, in Cinebench R20 and R23, the multicore scores (475 and 1131) are 7.2 and 7.1 times the single-core scores (66 and 159), respectively. This ratio is mathematically impossible for a 2-thread CPU under normal scaling, implying that the single-core results are disproportionately low. The cause may lie in the benchmark's sensitivity to clock speed or cache latency, but the data alone cannot explain the anomaly. What is clear is that the Celeron's single-thread performance is exceptionally weak—far weaker than its multi-thread performance relative to other CPUs. For real-world applications that rely on single-thread speed (e.g., spreadsheet recalculation, script execution), the chip will feel sluggish, while workloads that can leverage both cores will see comparatively better, though still low, throughput. The discrepancy also suggests that the Celeron's 2 MB shared L3 cache and 64 KB L1 per core may be insufficient for the working sets of modern software, further hampering single-thread efficiency. Overall, the data paints a picture of a processor that is barely adequate for basic tasks and best avoided for anything beyond light usage.