Celeron M 585 vs Core 2 Quad Q8400

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 M 585 vs Core 2 Quad Q8400 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 M 585 vs Core 2 Quad Q8400: Pros, Cons & Final Verdict

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

Celeron M 585

2008

Why buy it

✅Draws 1W instead of 95W, a 94W reduction.

Trade-offs

❌Lower PassMark (2,062 vs 2,076).
❌No boxed cooler included, unlike Core 2 Quad Q8400.

Core 2 Quad Q8400

2009

Why buy it

✅+0.7% higher PassMark.
✅Includes a boxed cooler (true), unlike Celeron M 585.

Trade-offs

❌Launch MSRP is still $183 MSRP, while Celeron M 585 mostly shows up through inconsistent older-market listings.
❌9400% higher power demand at 95W vs 1W.

Quick Answers

So, is Core 2 Quad Q8400 better than Celeron M 585?

It depends on what you want from the system. For gaming, Celeron M 585 is ahead with a 1.3% average FPS lead across 50 shared CPU game tests in our data. For rendering, compiling, streaming, and heavier multitasking, Core 2 Quad Q8400 pulls ahead with 0.7% better PassMark.

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

For streaming, content creation, and heavier multitasking, Core 2 Quad Q8400 is the stronger fit. You are getting 0.7% better PassMark, backed by 4 cores and 4 threads.

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

Core 2 Quad Q8400 is the better buy right now. Core 2 Quad Q8400 comes in at an unclear MSRP at $183 MSRP versus unclear MSRP, and it still gives you 0.7% better PassMark. The compromise is that Celeron M 585 is still the better pure gaming CPU with a 1.3% average FPS lead across 50 shared CPU game tests in our data. It is also 100.0% better value on MSRP (11.3 vs 0.0 PassMark/$), so you are getting the faster CPU without taking a value hit on paper.

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

Core 2 Quad Q8400 makes more sense long term for 2026 and beyond. You are getting a newer CPU generation (2009 vs 2008) and more multi-core headroom with 4 cores / 4 threads instead of 1/1. That extra compute headroom is more likely to matter as games, background tasks, and creator workloads get heavier.

Celeron M 585 vs Core 2 Quad Q8400 Technical Specifications

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

Celeron M 585

The Celeron M 585 is manufactured by Intel. It was released in 20 August 2008 (17 years ago). It is based on the Merom (2006−2008) architecture. It features 1 cores and 1 threads. Max frequency: 2.16 GHz. L2 cache: 1 MB. Built on 65 nm process technology. Socket: PGA478. Thermal design power (TDP): 1 MB. Passmark benchmark score: 2,062 points. Launch price was $70.

Core 2 Quad Q8400

The Core 2 Quad Q8400 is manufactured by Intel. It was released in 2008-01-01. It is based on the Yorkfield (2007−2009) architecture. It features 4 cores and 4 threads. Base frequency is 2.66 GHz, with boost up to 0.67 GHz. L3 cache: 0 kB. L2 cache: 4 MB (total). Built on 45 nm process technology. Socket: LGA775. Thermal design power (TDP): 95 Watt. Memory support: DDR1, DDR2, DDR3. Passmark benchmark score: 2,076 points. Launch price was $249.

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Processing Power

The Celeron M 585 packs 1 cores / 1 threads, while the Core 2 Quad Q8400 offers 4 cores / 4 threads — the Core 2 Quad Q8400 has 3 more cores. Boost clocks reach 2.16 GHz on the Celeron M 585 versus 0.67 GHz on the Core 2 Quad Q8400 — a 105.3% clock advantage for the Celeron M 585. The Celeron M 585 uses the Merom (2006−2008) architecture (65 nm), while the Core 2 Quad Q8400 uses Yorkfield (2007−2009) (45 nm). In PassMark, the Celeron M 585 scores 2,062 against the Core 2 Quad Q8400's 2,076 — a 0.7% lead for the Core 2 Quad Q8400.

Feature	Celeron M 585	Core 2 Quad Q8400
Cores / Threads	1 / 1	4 / 4+300%
Boost Clock	2.16 GHz+222%	0.67 GHz
Base Clock	—	2.66 GHz
L3 Cache	—	0 kB
L2 Cache	1 MB	4 MB (total)+300%
Process	65 nm	45 nm-31%
Architecture	Merom (2006−2008)	Yorkfield (2007−2009)
PassMark	2,062	2,076
Cinebench R23 Multi	—	852
Geekbench 6 Single	—	369
Geekbench 6 Multi	—	1,155

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Memory & Platform

The Celeron M 585 uses the PGA478 socket (PCIe 1.1), while the Core 2 Quad Q8400 uses LGA775 (PCIe 1.1) — making them incompatible on the same motherboard. Maximum memory speed reaches 800 on the Celeron M 585 versus DDR3 1333 MHz on the Core 2 Quad Q8400 — the Core 2 Quad Q8400 supports 66.6% faster memory, which can translate to measurable gains in memory-sensitive workloads. The Core 2 Quad Q8400 supports up to 16 GB of RAM compared to 4 GB — 300% more capacity for professional workloads. Both feature 2-channel memory with ECC support. Both provide 0 PCIe lanes. Chipset compatibility: GL40,GM45 (Celeron M 585) and Intel P45,Intel G41,Intel Q45,Intel X48,Intel G31 (Core 2 Quad Q8400).

Feature	Celeron M 585	Core 2 Quad Q8400
Socket	PGA478	LGA775
PCIe Generation	PCIe 1.1	PCIe 1.1
Max RAM Speed	800	DDR3 1333 MHz+67%
Max RAM Capacity	4 GB	16 GB+300%
RAM Channels	2	2
ECC Support	No	No
PCIe Lanes	0	0

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Advanced Features

Neither processor supports overclocking. Virtualization support: false (Celeron M 585) vs true (Core 2 Quad Q8400). Primary use case: Core 2 Quad Q8400 targets Desktop. Direct competitor: Celeron M 585 rivals Mobile Sempron SI-40.