
Pentium III 1266S vs Atom Z515

Pentium III 1266S

Atom Z515
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 Pentium III 1266S is positioned at rank 1140 and the Atom Z515 is on rank 894, so the Atom Z515 offers better cost-efficiency for playing games.
Avg price is the current average price collected from markets across the web.
Performance Per Dollar Pentium III 1266S
Performance Per Dollar Atom Z515
Performance Comparison
About PassMark🏆 Chipversus Verdict
🚀 Performance Leadership
| Insight | Pentium III 1266S | Atom Z515 |
|---|---|---|
| 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 (Tualatin (2000−2002) / 130 nm) | 🛑 Legacy (Silverthorne (2008−2010) / 45 nm) |
💎 Value Proposition
| Insight | Pentium III 1266S | Atom Z515 |
|---|---|---|
| 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 Pentium III 1266S and Atom Z515

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.

Atom Z515
The Atom Z515 is manufactured by Intel. It was released in 8 April 2009 (16 years ago). It is based on the Silverthorne (2008−2010) architecture. It features 1 cores and 1 threads. Base frequency is 1.2 GHz, with boost up to 1.2 GHz. L3 cache: 0 kB. L2 cache: 512 kB (per core). Built on 45 nm process technology. Socket: PBGA441. Thermal design power (TDP): 1.4 Watt. Memory support: unknown. Passmark benchmark score: 195 points. Launch price was $69.
Processing Power
Both the Pentium III 1266S and Atom Z515 share an identical 1-core/1-thread configuration. Boost clocks reach 1.27 GHz on the Pentium III 1266S versus 1.2 GHz on the Atom Z515 — a 5.7% clock advantage for the Pentium III 1266S. The Pentium III 1266S uses the Tualatin (2000−2002) architecture (130 nm), while the Atom Z515 uses Silverthorne (2008−2010) (45 nm). In PassMark, the Pentium III 1266S scores 210 against the Atom Z515's 195 — a 7.4% lead for the Pentium III 1266S. Both processors carry 0 kB of L3 cache.
| Feature | Pentium III 1266S | Atom Z515 |
|---|---|---|
| Cores / Threads | 1 / 1 | 1 / 1 |
| Boost Clock | 1.27 GHz+6% | 1.2 GHz |
| Base Clock | — | 1.2 GHz |
| L3 Cache | 0 kB | 0 kB |
| L2 Cache | 512 kB | 512 kB (per core) |
| Process | 130 nm | 45 nm-65% |
| Architecture | Tualatin (2000−2002) | Silverthorne (2008−2010) |
| PassMark | 210+8% | 195 |
Memory & Platform
The Pentium III 1266S uses the PGA370 socket (PCIe 1.1), while the Atom Z515 uses PBGA441 (PCIe 2.0) — making them incompatible on the same motherboard.
| Feature | Pentium III 1266S | Atom Z515 |
|---|---|---|
| Socket | PGA370 | PBGA441 |
| PCIe Generation | PCIe 1.1 | PCIe 2.0+82% |
| Max RAM Speed | — | DDR2-533 |
| Max RAM Capacity | — | 2 GB |
| RAM Channels | — | 1 |
| ECC Support | — | ❌ |
| PCIe Lanes | — | 0 |
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