
Atom Z520 vs Pentium III 1266S

Atom Z520

Pentium III 1266S
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 Atom Z520 is positioned at rank 523 and the Pentium III 1266S is on rank 1140, so the Atom Z520 offers better cost-efficiency for playing games.
Avg price is the current average price collected from markets across the web.
Performance Per Dollar Atom Z520
Performance Per Dollar Pentium III 1266S
Performance Comparison
About PassMark🏆 Chipversus Verdict
🚀 Performance Leadership
| Insight | Atom Z520 | Pentium III 1266S |
|---|---|---|
| Gaming | ❌ Lower gaming performance | ✅ Superior gaming performance |
| Workstation | ✅ Better multi-core power | ❌ Weaker in multi-core tasks |
| Price | ✅ More affordable ($0) | ⚠️ Higher cost ($20) |
| Longevity | 🛑 Legacy (Silverthorne (2008−2010) / 45 nm) | 🛑 Legacy (Tualatin (2000−2002) / 130 nm) |
💎 Value Proposition
| Insight | Atom Z520 | Pentium III 1266S |
|---|---|---|
| Cost Efficiency | ❌ Lower cost efficiency | ❌ Lower cost efficiency |
| Upfront Cost | ✅ More affordable ($0) | ⚠️ Higher cost ($20) |
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 Atom Z520 and Pentium III 1266S

Atom Z520
The Atom Z520 is manufactured by Intel. It was released in 2 April 2008 (17 years ago). It is based on the Silverthorne (2008−2010) architecture. It features 1 cores and 2 threads. Base frequency is 1.33 GHz, with boost up to 0.03 GHz. L3 cache: 0 kB. L2 cache: 512 kB. Built on 45 nm process technology. Socket: PBGA441. Thermal design power (TDP): 2 Watt. Passmark benchmark score: 215 points. Launch price was $65.

Pentium III 1266S
The Pentium III 1266S is manufactured by Intel. It was released in 2007-01-01. It is based on the Tualatin (2000−2002) architecture. It features 1 cores and 1 threads. Max frequency: 1.27 GHz. L3 cache: 0 kB. L2 cache: 512 kB. Built on 130 nm process technology. Socket: PGA370. Thermal design power (TDP): 30 Watt. Passmark benchmark score: 210 points. Launch price was $69.
Processing Power
The Atom Z520 packs 1 cores / 2 threads, matching the Pentium III 1266S's 1 cores. Boost clocks reach 0.03 GHz on the Atom Z520 versus 1.27 GHz on the Pentium III 1266S — a 190.8% clock advantage for the Pentium III 1266S. The Atom Z520 uses the Silverthorne (2008−2010) architecture (45 nm), while the Pentium III 1266S uses Tualatin (2000−2002) (130 nm). In PassMark, the Atom Z520 scores 215 against the Pentium III 1266S's 210 — a 2.4% lead for the Atom Z520. Both processors carry 0 kB of L3 cache.
| Feature | Atom Z520 | Pentium III 1266S |
|---|---|---|
| Cores / Threads | 1 / 2 | 1 / 1 |
| Boost Clock | 0.03 GHz | 1.27 GHz+4133% |
| Base Clock | 1.33 GHz | — |
| L3 Cache | 0 kB | 0 kB |
| L2 Cache | 512 kB | 512 kB |
| Process | 45 nm-65% | 130 nm |
| Architecture | Silverthorne (2008−2010) | Tualatin (2000−2002) |
| PassMark | 215+2% | 210 |
Memory & Platform
The Atom Z520 uses the PBGA441 socket (PCIe 2.0), while the Pentium III 1266S uses PGA370 (PCIe 1.1) — making them incompatible on the same motherboard.
| Feature | Atom Z520 | Pentium III 1266S |
|---|---|---|
| Socket | PBGA441 | PGA370 |
| PCIe Generation | PCIe 2.0+82% | PCIe 1.1 |
| Max RAM Speed | DDR2-533 | — |
| Max RAM Capacity | 2 GB | — |
| RAM Channels | 1 | — |
| ECC Support | ❌ | — |
| PCIe Lanes | 0 | — |
Advanced Features
Virtualization: VT-x (Atom Z520) / not specified (Pentium III 1266S). Primary use case: Atom Z520 targets Mobile.
| Feature | Atom Z520 | Pentium III 1266S |
|---|---|---|
| Integrated GPU | No | — |
| Unlocked | No | — |
| AVX-512 | No | — |
| Virtualization | VT-x | — |
| Target Use | Mobile | — |
Top Performing CPUs
The most powerful cpus ranked by PassMark CPU Mark benchmark scores.











