Intel Celeron 3865U Chromebooks

The Intel Celeron 3865U is a dual-core, ultra-low-voltage processor from Intel’s Kaby Lake-U architecture, launched in Q1 2017. Manufactured on a 14nm process, this chip was positioned as a budget entry point for thin-and-light notebooks and compact desktop systems. Running at a fixed 1.8 GHz with no Turbo Boost capability and lacking Hyperthreading, the 3865U delivers consistent but modest performance. Its 15W TDP (configurable down to 10W) makes it suitable for passively-cooled designs or compact systems where thermal management is constrained.

In the Chrome OS ecosystem, the Celeron 3865U found its home exclusively in Chromebox desktop units rather than laptop Chromebooks. Manufacturers like Acer, ASUS, and CTL used this processor in compact desktop systems released around 2018, targeting digital signage, kiosk deployments, educational computer labs, and basic office workstations. The processor includes Intel HD Graphics 610 with 12 execution units, capable of driving dual displays and handling hardware-accelerated video decode. At launch, these Chromeboxes typically sold between $250 and $550 depending on RAM and storage configurations.

The 3865U represents a transitional period in Chrome OS hardware. It arrived after the Apollo Lake mobile Celerons but before the more efficient Gemini Lake generation. While technically a “U” series ultrabook-class chip rather than an “N” series mobile processor, it offered similar entry-level performance characteristics. All Chromeboxes using this processor have since been discontinued, with most reaching their Auto Update Expiration dates. The Acer Chromebox CXI3 remains the exception, with Chrome OS support continuing until June 2028.

Performance

The Intel Celeron 3865U scores approximately 13,000 on the Octane 2.0 JavaScript benchmark, a key metric for Chrome OS responsiveness. This places it notably below newer Celeron processors: the N4000 achieves around 20,000, the N4020 matches that at 20,000, and the N4120 reaches 32,000. However, the 3865U outperforms older Bay Trail and Braswell Celerons that scored in the 7,000-9,000 range.

In PassMark CPU Mark multi-threaded testing, the 3865U scores approximately 1,347 points, positioning it between the AMD A4-9120 and the older Intel Core i3-2377M. Geekbench 5 testing shows single-core scores around 443 points and multi-core scores around 839 points. Geekbench 6 results indicate single-core performance of 392 and multi-core of 693, calibrated against modern processors. Cinebench R15 benchmarks show 72 points single-core and 142 points multi-core, placing it in the bottom tier of mobile processors tested.

In practical terms, these numbers translate to adequate performance for basic Chrome OS tasks: web browsing with a modest number of tabs, Google Docs editing, email, and video streaming. NotebookCheck’s assessment characterized the 3865U as “only suited for entry level tasks like office, web surfing and multimedia,” noting that the “missing Turbo Boost and the low clock speeds” particularly constrain single-thread performance. The processor handles 1080p and 4K video playback smoothly thanks to dedicated video decode hardware, but demanding workloads will feel sluggish. This is fundamentally a “light-duty” processor where user expectations must be calibrated to match.

Ideal Use Cases

Chromeboxes with the Intel Celeron 3865U excel as dedicated-purpose computing devices. Digital signage deployments, information kiosks, point-of-sale systems, and lobby display terminals benefit from the compact form factor, low power consumption, and ChromeOS’s automatic update model that minimizes maintenance overhead. The near-silent operation in well-ventilated Chromebox enclosures suits environments where noise matters, such as libraries, reception areas, or quiet offices.

For basic desktop computing needs, 3865U Chromeboxes deliver reasonable value, particularly on the secondary market. Web browsing, email, document editing in Google Workspace, video conferencing, and media streaming all function adequately. Hardware Haven’s testing demonstrated that these units idle at just 1.5 watts, making them remarkably efficient home servers for light workloads. Enthusiasts have successfully repurposed 3865U Chromeboxes as Proxmox virtualization servers, Jellyfin media servers, and Minecraft game servers after installing custom firmware.

However, the 3865U shows its limitations with heavier workloads. Power users who regularly work with many browser tabs simultaneously, run demanding Android applications, or need responsive performance in Linux apps through Crostini should look elsewhere. The dual-core design without Hyperthreading constrains multitasking capability. Professional productivity work, content creation, and development workflows will feel frustratingly slow. This processor serves best when dedicated to specific, lightweight tasks rather than general-purpose computing.

What to Look For

When considering an Intel Celeron 3865U Chromebox, the Auto Update Expiration date should guide your decision. The ASUS Chromebox 3 and CTL Chromebox CBx1 reached their AUE date in June 2024, meaning they no longer receive Chrome OS updates, including security patches. Only the Acer Chromebox CXI3 retains support until June 2028, making it the only viable option for anyone wanting continued Chrome OS updates. For buyers interested in Linux server projects or alternative uses after flashing custom firmware, the expired AUE becomes less relevant.

RAM configuration significantly impacts the user experience. The base 4GB configurations work for light tasks but show strain under multitasking. The Acer Chromebox CXI3 offered variants with 8GB and 16GB RAM, with the latter providing meaningful headroom for tab-heavy browsing and multiple applications. The ASUS and Acer Chromeboxes include dual RAM slots allowing for user upgrades, which has made them attractive to hobbyists. If purchasing used, prioritize units with 8GB or higher, or verify upgrade potential before buying.

Storage ranges from 32GB to 64GB across available configurations, with both eMMC and SSD variants depending on model. The SSD-equipped Acer and ASUS units deliver faster boot times and snappier application launches than eMMC storage. All 3865U Chromeboxes include microSD card slots for expansion. For server repurposing, models with M.2 slots enable storage upgrades to faster or larger drives after installation.

Connectivity proves surprisingly robust on these Chromeboxes. All three manufacturers included Gigabit Ethernet, multiple USB 3.0 ports, USB-C, HDMI output, and Wi-Fi 5 (802.11ac) with Bluetooth 4.2. This port selection handles most desktop use cases without adapters. The HDMI 1.4 specification limits 4K output to 30Hz, adequate for productivity but less ideal for media consumption. Both ASUS and Acer Chromeboxes support DisplayPort Alt Mode over USB-C for secondary display connections.

Given that all 3865U Chromeboxes are discontinued, pricing on the used market varies widely. Hardware Haven found units selling for under $40, representing exceptional value for home server projects. For continued Chrome OS desktop use, the Acer Chromebox CXI3 with its 2028 support date commands a premium but remains the only sensible choice. Factor the remaining support window and intended use case when evaluating used market pricing.