Celeron 3865U vs Pentium G840

PassMark CPU Mark evaluates processor speed through complex mathematical computations. It provides a reliable metric to compare multi-core performance, where higher scores indicate faster processing for multitasking, gaming, and heavy workloads.

Celeron 3865U vs Pentium G840 FPS Benchmarks

Predicted gaming performance across popular games. Tested paired with GeForce RTX 5090 to isolate CPU performance.

Search any supported game below to compare 1080p FPS for both components.

Celeron 3865U vs Pentium G840: Pros, Cons & Final Verdict

See where each CPU makes more sense in practice: gaming, heavier work, platform cost, power draw, and upgrade path.

Celeron 3865U

2017

Why buy it

✅Draws 15W instead of 65W, a 50W reduction.
✅100+% more PCIe lanes (10 vs 0) for storage and expansion-heavy builds.
✅Integrated graphics onboard with Intel HD Graphics 610, while Pentium G840 needs a discrete GPU.

Trade-offs

❌Lower PassMark (1,343 vs 1,367).
❌Smaller total L3 cache (2 MB vs 3 MB).

Pentium G840

2011

Why buy it

✅+50% larger total L3 cache (3 MB vs 2 MB).

Trade-offs

❌Launch MSRP is still $64 MSRP, while Celeron 3865U mostly shows up through inconsistent older-market listings.
❌333.3% higher power demand at 65W vs 15W.
❌No integrated graphics, while Celeron 3865U can still boot and troubleshoot without a discrete GPU.

Quick Answers

So, is Pentium G840 better than Celeron 3865U?

Yes. Pentium G840 is the better all-around CPU here. It gives you a 0.1% average FPS lead across 50 shared CPU game tests in our data and 1.8% better PassMark, which is enough to make it the stronger overall pick.

Which one is better for gaming?

If gaming is the priority, Pentium G840 is the better pick. According to our tests, it delivers 0.1% more average FPS across 50 shared CPU game tests.

Which one is better for streaming, content creation, and heavy multitasking?

For streaming, content creation, and heavier multitasking, Pentium G840 is the stronger fit. You are getting 1.8% better PassMark, backed by 2 cores and 2 threads. It also has the larger cache pool with 50% larger total L3 cache (3 MB vs 2 MB).

Which one is the smarter buy today, not just the cheaper CPU?

Pentium G840 is the better buy right now. Pentium G840 comes in at an unclear MSRP at $64 MSRP versus unclear MSRP, and it still gives you a 0.1% average FPS lead across 50 shared CPU game tests in our data. It is also 100.0% better value on MSRP (21.4 vs 0.0 PassMark/$), so you are getting the faster CPU without taking a value hit on paper.

Which one is more future-proof for 2026 and beyond?

Celeron 3865U makes more sense long term for 2026 and beyond. You are getting a newer CPU generation (2017 vs 2011). That makes it the safer long-term bet.

Celeron 3865U vs Pentium G840 Technical Specifications

Side-by-side specs, architecture details, clocks, memory, power, and platform differences.

Celeron 3865U

The Celeron 3865U is manufactured by Intel. It was released in 3 January 2017 (8 years ago). It is based on the Kaby Lake-U (2017) architecture. It features 2 cores and 2 threads. Base frequency is 1.8 GHz, with boost up to 1.8 GHz. L3 cache: 2 MB (total). L2 cache: 256K (per core). Built on 14 nm process technology. Socket: BGA1356. Thermal design power (TDP): 15 Watt. Memory support: DDR3, DDR4. Passmark benchmark score: 1,343 points. Launch price was $107.

Pentium G840

The Pentium G840 is manufactured by Intel. It was released in 22 May 2011 (14 years ago). It is based on the Sandy Bridge (2011−2013) architecture. It features 2 cores and 2 threads. Base frequency is 2.8 GHz, with boost up to 2.8 GHz. L3 cache: 3 MB (total). L2 cache: 256 kB (per core). Built on 32 nm process technology. Socket: LGA1155. Thermal design power (TDP): 65 Watt. Memory support: DDR3. Passmark benchmark score: 1,367 points. Launch price was $60.

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Processing Power

Both the Celeron 3865U and Pentium G840 share an identical 2-core/2-thread configuration. Boost clocks reach 1.8 GHz on the Celeron 3865U versus 2.8 GHz on the Pentium G840 — a 43.5% clock advantage for the Pentium G840 (base: 1.8 GHz vs 2.8 GHz). The Celeron 3865U uses the Kaby Lake-U (2017) architecture (14 nm), while the Pentium G840 uses Sandy Bridge (2011−2013) (32 nm). In PassMark, the Celeron 3865U scores 1,343 against the Pentium G840's 1,367 — a 1.8% lead for the Pentium G840. L3 cache: 2 MB (total) on the Celeron 3865U vs 3 MB (total) on the Pentium G840.

Feature	Celeron 3865U	Pentium G840
Cores / Threads	2 / 2	2 / 2
Boost Clock	1.8 GHz	2.8 GHz+56%
Base Clock	1.8 GHz	2.8 GHz+56%
L3 Cache	2 MB (total)	3 MB (total)+50%
L2 Cache	256K (per core)	256 kB (per core)
Process	14 nm-56%	32 nm
Architecture	Kaby Lake-U (2017)	Sandy Bridge (2011−2013)
PassMark	1,343	1,367+2%
Geekbench 6 Single	389	—
Geekbench 6 Multi	674	—

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Memory & Platform

The Celeron 3865U uses the BGA1356 socket (PCIe 3.0), while the Pentium G840 uses LGA1155 (PCIe 2.0) — making them incompatible on the same motherboard.

Feature	Celeron 3865U	Pentium G840
Socket	BGA1356	LGA1155
PCIe Generation	PCIe 3.0+50%	PCIe 2.0
Max RAM Speed	DDR4-2133 / LPDDR3-1866	—
Max RAM Capacity	32 GB	—
RAM Channels	2	—
ECC Support	No	—
PCIe Lanes	10	—

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Advanced Features

Virtualization: VT-x / VT-d / EPT (Celeron 3865U) / not specified (Pentium G840). The Celeron 3865U includes integrated graphics (Intel HD Graphics 610), while the Pentium G840 requires a dedicated GPU. Primary use case: Celeron 3865U targets Entry-level. Direct competitor: Celeron 3865U rivals Pentium Gold 4415U.