A8-3870K vs Athlon II X4 645

A8-3870K vs Athlon II X4 645 Performance Spectrum

A8-3870K

4 / 4

2,360

0.0%

Ryzen Threadripper PRO 7955WX

Ryzen Threadripper 3990X

Athlon II X4 645

4 / 4

2,375

+0.6%

Ryzen Threadripper PRO 7955WX

Ryzen Threadripper 3990X

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.

A8-3870K vs Athlon II X4 645 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.

A8-3870K vs Athlon II X4 645: Pros, Cons & Final Verdict

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

A8-3870K

2011

Why buy it

✅25% more PCIe lanes (20 vs 16) for storage and expansion-heavy builds.
✅Integrated graphics onboard with Radeon HD 6550D, while Athlon II X4 645 needs a discrete GPU.

Trade-offs

❌Lower Geekbench single-core performance for gaming (380 vs 399).
❌Lower PassMark (2,360 vs 2,375).

Athlon II X4 645

2010

Why buy it

✅+5% higher Geekbench single-core performance for gaming and desktop responsiveness.
✅Draws 95W instead of 100W, a 5W reduction.

Trade-offs

❌Launch MSRP is still $126 MSRP, while A8-3870K mostly shows up through inconsistent older-market listings.
❌No integrated graphics, while A8-3870K can still boot and troubleshoot without a discrete GPU.

Quick Answers

So, is Athlon II X4 645 better than A8-3870K?

Yes. Athlon II X4 645 is the better all-around CPU here. It gives you a 0.8% average FPS lead across 50 shared CPU game tests in our data and 0.6% better PassMark, which is enough to make it the stronger overall pick.

Which one is better for gaming?

If gaming is the priority, Athlon II X4 645 is the better pick. According to our tests, it delivers 0.8% 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, Athlon II X4 645 is the stronger fit. You are getting 0.6% better PassMark, backed by 4 cores and 4 threads.

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

Athlon II X4 645 is the better buy right now. Athlon II X4 645 comes in at an unclear MSRP at $126 MSRP versus unclear MSRP, and it still gives you a 0.8% average FPS lead across 50 shared CPU game tests in our data. It is also 100.0% better value on MSRP (18.8 vs 0.0 PassMark/$), so you are getting the faster CPU without taking a value hit on paper.

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

A8-3870K makes more sense long term for 2026 and beyond. You are getting a newer CPU generation (2011 vs 2010). That makes it the safer long-term bet.

A8-3870K vs Athlon II X4 645 Technical Specifications

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

A8-3870K

The A8-3870K is manufactured by AMD. It was released in 2014-01-01. It is based on the Llano (2011−2012) architecture. It features 4 cores and 4 threads. Base frequency is 3 GHz, with boost up to 3 GHz. L3 cache: 0 kB. L2 cache: 1 MB (per core). Built on 32 nm process technology. Socket: FM1. Thermal design power (TDP): 100 Watt. Memory support: DDR3. Passmark benchmark score: 2,360 points. Launch price was $90.

Athlon II X4 645

The Athlon II X4 645 is manufactured by AMD. It was released in 21 September 2010 (15 years ago). It is based on the Propus (2009−2011) architecture. It features 4 cores and 4 threads. Base frequency is 3.1 GHz, with boost up to 3.1 GHz. L3 cache: 0 kB. L2 cache: 512 kB (per core). Built on 45 nm process technology. Socket: AM3. Thermal design power (TDP): 95 Watt. Memory support: DDR3. Passmark benchmark score: 2,375 points. Launch price was $80.

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Processing Power

Both the A8-3870K and Athlon II X4 645 share an identical 4-core/4-thread configuration. Boost clocks reach 3 GHz on the A8-3870K versus 3.1 GHz on the Athlon II X4 645 — a 3.3% clock advantage for the Athlon II X4 645 (base: 3 GHz vs 3.1 GHz). The A8-3870K uses the Llano (2011−2012) architecture (32 nm), while the Athlon II X4 645 uses Propus (2009−2011) (45 nm). In PassMark, the A8-3870K scores 2,360 against the Athlon II X4 645's 2,375 — a 0.6% lead for the Athlon II X4 645. Geekbench 6 single-core — the metric most relevant to gaming — records 380 vs 399, a 4.9% lead for the Athlon II X4 645 that directly translates to higher frame rates. Both processors carry 0 kB of L3 cache.

Feature	A8-3870K	Athlon II X4 645
Cores / Threads	4 / 4	4 / 4
Boost Clock	3 GHz	3.1 GHz+3%
Base Clock	3 GHz	3.1 GHz+3%
L3 Cache	0 kB	0 kB
L2 Cache	1 MB (per core)+100%	512 kB (per core)
Process	32 nm-29%	45 nm
Architecture	Llano (2011−2012)	Propus (2009−2011)
PassMark	2,360	2,375
Cinebench R23 Multi	—	1,374
Geekbench 6 Single	380	399+5%
Geekbench 6 Multi	—	1,374

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Memory & Platform

The A8-3870K uses the FM1 socket (PCIe 2.0), while the Athlon II X4 645 uses AM3 (PCIe 2.0) — making them incompatible on the same motherboard. Maximum memory speed reaches DDR3-1866 on the A8-3870K versus DDR3-1333 on the Athlon II X4 645 — the A8-3870K supports 40% faster memory, which can translate to measurable gains in memory-sensitive workloads. The A8-3870K supports up to 32 GB of RAM compared to 16 GB — 100% more capacity for professional workloads. Both feature 2-channel memory with ECC support. PCIe lanes: 20 (A8-3870K) vs 16 (Athlon II X4 645) — the A8-3870K offers 4 more lanes for additional GPUs or NVMe drives. Chipset compatibility: A55,A75 (A8-3870K) and AMD 700 Series,AMD 800 Series,AMD 900 Series (Athlon II X4 645).

Feature	A8-3870K	Athlon II X4 645
Socket	FM1	AM3
PCIe Generation	PCIe 2.0	PCIe 2.0
Max RAM Speed	DDR3-1866+40%	DDR3-1333
Max RAM Capacity	32 GB+100%	16 GB
RAM Channels	2	2
ECC Support	No	No
PCIe Lanes	20+25%	16

🔧

Advanced Features

Virtualization support: AMD-V (A8-3870K) vs Yes (Athlon II X4 645). The A8-3870K includes integrated graphics (Radeon HD 6550D), while the Athlon II X4 645 requires a dedicated GPU. Primary use case: A8-3870K targets Budget Gaming Desktop, Athlon II X4 645 targets Desktop. Direct competitor: A8-3870K rivals Core i3-2125.