Athlon II X4 645 vs A8-3870K
Athlon II X4 645
A8-3870K
Performance Spectrum - CPU
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.
Value Upgrade Path
This is the official ChipVERSUS Value Rating, comparing raw performance (PassMark) per dollar. Components placed above yours deliver better value for money. The Athlon II X4 645 is positioned at rank 819 and the A8-3870K is on rank 502, so the A8-3870K offers better cost-efficiency for playing games.
Avg price is the current average price collected from markets across the web.
Performance Per Dollar Athlon II X4 645
Performance Per Dollar A8-3870K
Performance Comparison
About PassMark🏆 Chipversus Verdict
🚀 Performance Leadership
| Insight | Athlon II X4 645 | A8-3870K |
|---|---|---|
| Gaming | ✅ Superior gaming performance | ❌ Lower gaming performance |
| Workstation | ✅ Better multi-core power | ❌ Weaker in multi-core tasks |
| Price | ⚠️ Higher cost ($20) | ✅ More affordable ($0) |
| Longevity | 🛑 Legacy (Propus (2009−2011) / 45 nm) | 🛑 Legacy (Llano (2011−2012) / 32 nm) |
💎 Value Proposition
| Insight | Athlon II X4 645 | A8-3870K |
|---|---|---|
| Cost Efficiency | ❌ Lower cost efficiency | ❌ Lower cost efficiency |
| Upfront Cost | ⚠️ Higher cost ($20) | ✅ More affordable ($0) |
Performance Check
To accurately isolate CPU performance, all benchmarks below use an NVIDIA RTX 4090 as the reference GPU. This eliminates GPU-side bottlenecks and highlights pure processing throughput differences between the CPUs.
Note: Real-world results may vary based on your actual GPU. CPU performance impact is more visible in processing-intensive titles and high-refresh-rate gaming scenarios.
Technical Specifications
Side-by-side comparison of Athlon II X4 645 and A8-3870K
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.
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.
Processing Power
Both the Athlon II X4 645 and A8-3870K share an identical 4-core/4-thread configuration. Boost clocks reach 3.1 GHz on the Athlon II X4 645 versus 3 GHz on the A8-3870K — a 3.3% clock advantage for the Athlon II X4 645 (base: 3.1 GHz vs 3 GHz). The Athlon II X4 645 uses the Propus (2009−2011) architecture (45 nm), while the A8-3870K uses Llano (2011−2012) (32 nm). In PassMark, the Athlon II X4 645 scores 2,375 against the A8-3870K's 2,360 — a 0.6% lead for the Athlon II X4 645. Geekbench 6 single-core — the metric most relevant to gaming — records 399 vs 380, 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 | Athlon II X4 645 | A8-3870K |
|---|---|---|
| Cores / Threads | 4 / 4 | 4 / 4 |
| Boost Clock | 3.1 GHz+3% | 3 GHz |
| Base Clock | 3.1 GHz+3% | 3 GHz |
| L3 Cache | 0 kB | 0 kB |
| L2 Cache | 512 kB (per core) | 1 MB (per core)+100% |
| Process | 45 nm | 32 nm-29% |
| Architecture | Propus (2009−2011) | Llano (2011−2012) |
| PassMark | 2,375 | 2,360 |
| Cinebench R23 Multi | 1,374 | — |
| Geekbench 6 Single | 399+5% | 380 |
| Geekbench 6 Multi | 1,374 | — |
Memory & Platform
The Athlon II X4 645 uses the AM3 socket (PCIe 2.0), while the A8-3870K uses FM1 (PCIe 2.0) — making them incompatible on the same motherboard. Both support up to DDR3-1333 memory speed. The A8-3870K supports up to 32 GB of RAM compared to 16 GB — 66.7% more capacity for professional workloads. Both feature 2-channel memory with ECC support. PCIe lanes: 16 (Athlon II X4 645) vs 20 (A8-3870K) — the A8-3870K offers 4 more lanes for additional GPUs or NVMe drives. Chipset compatibility: AMD 700 Series,AMD 800 Series,AMD 900 Series (Athlon II X4 645) and A55,A75 (A8-3870K).
| Feature | Athlon II X4 645 | A8-3870K |
|---|---|---|
| Socket | AM3 | FM1 |
| PCIe Generation | PCIe 2.0 | PCIe 2.0 |
| Max RAM Speed | DDR3-1333 | DDR3-1866 |
| Max RAM Capacity | 16 GB | 32 GB+100% |
| RAM Channels | 2 | 2 |
| ECC Support | ❌ | ❌ |
| PCIe Lanes | 16 | 20+25% |
Advanced Features
Virtualization support: Yes (Athlon II X4 645) vs AMD-V (A8-3870K). The A8-3870K includes integrated graphics (Radeon HD 6550D), while the Athlon II X4 645 requires a dedicated GPU. Primary use case: Athlon II X4 645 targets Desktop, A8-3870K targets Budget Gaming Desktop. Direct competitor: A8-3870K rivals Core i3-2125.
| Feature | Athlon II X4 645 | A8-3870K |
|---|---|---|
| Integrated GPU | No | Yes |
| IGPU Model | — | Radeon HD 6550D |
| Unlocked | — | Yes |
| AVX-512 | No | No |
| Virtualization | Yes | AMD-V |
| Target Use | Desktop | Budget Gaming Desktop |
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