Celeron 3865U vs Ryzen 9 5900X

CPU

GPU

Celeron 3865U

2 Cores2 Thrd15 WWMax: 1.8 GHz2017

Similar parts

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Ryzen 9 5900X

12 Cores24 Thrd105 WWMax: 4.8 GHz2020

Ryzen family

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Celeron 3865U vs Ryzen 9 5900X Performance Spectrum

Celeron 3865U

2 / 2

1,343

0.0%

38,955

+2800.6%

Ryzen Threadripper 9960X

Ryzen Threadripper PRO 9975WX

About PassMark

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 Ryzen 9 5900X 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 Ryzen 9 5900X: 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 105W, a 90W reduction.
✅Integrated graphics onboard with Intel HD Graphics 610, while Ryzen 9 5900X needs a discrete GPU.

Trade-offs

❌Worse for gaming: lower average FPS than Ryzen 9 5900X across 50 shared CPU benchmark tests.
❌Lower Geekbench multi-core (674 vs 11,888).
❌Smaller total L3 cache (2 MB vs 64 MB).

Ryzen 9 5900X

2020

Why buy it

✅Better for gaming: +742.2% higher average FPS across 50 shared CPU benchmark tests.
✅+3100% larger total L3 cache (64 MB vs 2 MB).
✅140% more PCIe lanes (24 vs 10) for storage and expansion-heavy builds.

Trade-offs

❌Launch MSRP is still $549 MSRP, while Celeron 3865U mostly shows up through inconsistent older-market listings.
❌600% higher power demand at 105W vs 15W.
❌No integrated graphics, while Celeron 3865U can still boot and troubleshoot without a discrete GPU.

Quick Answers

So, is Ryzen 9 5900X better than Celeron 3865U?

Yes. Ryzen 9 5900X is the better all-around CPU here. It gives you a 742.2% average FPS lead across 50 shared CPU game tests in our data, 1663.8% better Geekbench multi-core, 2800.6% higher PassMark, and the stronger long-term platform, which is enough to make it the stronger overall pick.

Which one is better for gaming?

If gaming is the priority, Ryzen 9 5900X is the better pick. According to our tests, it delivers 742.2% 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, Ryzen 9 5900X is the stronger fit. You are getting 1663.8% better Geekbench multi-core, backed by 12 cores and 24 threads. It also has the larger cache pool with 3100% larger total L3 cache (64 MB vs 2 MB).

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

Ryzen 9 5900X is the better buy right now. Ryzen 9 5900X comes in at an unclear MSRP at $549 MSRP versus unclear MSRP, and it still gives you a 742.2% average FPS lead across 50 shared CPU game tests in our data. It is also 100.0% better value on MSRP (71.0 vs 0.0 PassMark/$), so you are getting the faster CPU without taking a value hit on paper.

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

Ryzen 9 5900X makes more sense long term for 2026 and beyond. You are getting a newer CPU generation (2020 vs 2017), 3100% larger total L3 cache (64 MB vs 2 MB), and more multi-core headroom with 12 cores / 24 threads instead of 2/2. That extra compute headroom is more likely to matter as games, background tasks, and creator workloads get heavier.

Celeron 3865U vs Ryzen 9 5900X 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.

Ryzen 9 5900X

The Ryzen 9 5900X is manufactured by AMD. It was released in 5 November 2020 (5 years ago). It is based on the Vermeer (Zen3) (2020−2022) architecture. It features 12 cores and 24 threads. Base frequency is 3.7 GHz, with boost up to 4.8 GHz. L3 cache: 64 MB. L2 cache: 512K (per core). Built on 7 nm, 12 nm process technology. Socket: AM4. Thermal design power (TDP): 105 Watt. Memory support: DDR4-3200. Passmark benchmark score: 38,955 points. Launch price was $549.

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Processing Power

The Celeron 3865U packs 2 cores / 2 threads, while the Ryzen 9 5900X offers 12 cores / 24 threads — the Ryzen 9 5900X has 10 more cores. Boost clocks reach 1.8 GHz on the Celeron 3865U versus 4.8 GHz on the Ryzen 9 5900X — a 90.9% clock advantage for the Ryzen 9 5900X (base: 1.8 GHz vs 3.7 GHz). The Celeron 3865U uses the Kaby Lake-U (2017) architecture (14 nm), while the Ryzen 9 5900X uses Vermeer (Zen3) (2020−2022) (7 nm, 12 nm). In PassMark, the Celeron 3865U scores 1,343 against the Ryzen 9 5900X's 38,955 — a 186.7% lead for the Ryzen 9 5900X. Geekbench 6 single-core — the metric most relevant to gaming — records 389 vs 2,174, a 139.3% lead for the Ryzen 9 5900X that directly translates to higher frame rates. Multi-core Geekbench: 674 vs 11,888 (178.5% advantage for the Ryzen 9 5900X). L3 cache: 2 MB (total) on the Celeron 3865U vs 64 MB on the Ryzen 9 5900X.

Feature	Celeron 3865U	Ryzen 9 5900X
Cores / Threads	2 / 2	12 / 24+500%
Boost Clock	1.8 GHz	4.8 GHz+167%
Base Clock	1.8 GHz	3.7 GHz+106%
L3 Cache	2 MB (total)	64 MB+3100%
L2 Cache	256K (per core)	512K (per core)+100%
Process	14 nm	7 nm, 12 nm-50%
Architecture	Kaby Lake-U (2017)	Vermeer (Zen3) (2020−2022)
PassMark	1,343	38,955+2801%
Cinebench R23 Multi	—	21,000
Geekbench 6 Single	389	2,174+459%
Geekbench 6 Multi	674	11,888+1664%

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Memory & Platform

The Celeron 3865U uses the BGA1356 socket (PCIe 3.0), while the Ryzen 9 5900X uses AM4 (PCIe 4.0) — making them incompatible on the same motherboard. Maximum memory speed reaches DDR4-2133 / LPDDR3-1866 on the Celeron 3865U versus DDR4-3200 on the Ryzen 9 5900X — the Ryzen 9 5900X supports 50% faster memory, which can translate to measurable gains in memory-sensitive workloads. The Ryzen 9 5900X supports up to 128 GB of RAM compared to 32 GB — 300% more capacity for professional workloads. Both feature 2-channel memory with ECC support. PCIe lanes: 10 (Celeron 3865U) vs 24 (Ryzen 9 5900X) — the Ryzen 9 5900X offers 14 more lanes for additional GPUs or NVMe drives. Chipset compatibility: 100-series,200-series (Celeron 3865U) and A320,B350,X370,B450,X470,B550,X570 (Ryzen 9 5900X).

Feature	Celeron 3865U	Ryzen 9 5900X
Socket	BGA1356	AM4
PCIe Generation	PCIe 3.0	PCIe 4.0+33%
Max RAM Speed	DDR4-2133 / LPDDR3-1866	DDR4-3200+50%
Max RAM Capacity	32 GB	128 GB+300%
RAM Channels	2	2
ECC Support	No	Yes
PCIe Lanes	10	24+140%

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Advanced Features

Only the Ryzen 9 5900X has an unlocked multiplier for overclocking — a significant advantage for enthusiasts seeking extra performance. Virtualization support: VT-x / VT-d / EPT (Celeron 3865U) vs AMD-V (Ryzen 9 5900X). The Celeron 3865U includes integrated graphics (Intel HD Graphics 610), while the Ryzen 9 5900X requires a dedicated GPU. Primary use case: Celeron 3865U targets Entry-level, Ryzen 9 5900X targets Workstation. Direct competitor: Celeron 3865U rivals Pentium Gold 4415U; Ryzen 9 5900X rivals Core i9-12900K.