Atom Z515 vs Pentium III 1266S

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.

Atom Z515 vs Pentium III 1266S 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.

Atom Z515 vs Pentium III 1266S: Pros, Cons & Final Verdict

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

Atom Z515

2009

Why buy it

Trade-offs

❌Lower PassMark (195 vs 210).
❌2066.7% higher power demand at 650W vs 30W.

Pentium III 1266S

2001

Why buy it

✅Draws 30W instead of 650W, a 620W reduction.

Trade-offs

❌Launch MSRP is still $369 MSRP, while Atom Z515 mostly shows up through inconsistent older-market listings.

Quick Answers

So, is Pentium III 1266S better than Atom Z515?

Yes. Pentium III 1266S is the better all-around CPU here. It gives you 7.7% better PassMark, which is enough to make it the stronger overall pick.

Which one is better for gaming?

If gaming is the priority, Pentium III 1266S has the edge because it leads the single-thread side of this matchup with 5.8% higher max boost clock.

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

For streaming, content creation, and heavier multitasking, Pentium III 1266S is the stronger fit. You are getting 7.7% better PassMark, backed by 1 cores and 1 threads.

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

Pentium III 1266S is the better buy right now. Pentium III 1266S comes in at an unclear MSRP at $369 MSRP versus unclear MSRP, and it still gives you 7.7% higher PassMark. It is also 100.0% better value on MSRP (0.6 vs 0.0 PassMark/$), so you are getting the faster CPU without taking a value hit on paper.

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

Atom Z515 makes more sense long term for 2026 and beyond. You are getting a newer CPU generation (2009 vs 2001). That makes it the safer long-term bet.

Atom Z515 vs Pentium III 1266S Technical Specifications

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

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.

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.

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Processing Power

Both the Atom Z515 and Pentium III 1266S share an identical 1-core/1-thread configuration. Boost clocks reach 1.2 GHz on the Atom Z515 versus 1.27 GHz on the Pentium III 1266S — a 5.7% clock advantage for the Pentium III 1266S. The Atom Z515 uses the Silverthorne (2008−2010) architecture (45 nm), while the Pentium III 1266S uses Tualatin (2000−2002) (130 nm). In PassMark, the Atom Z515 scores 195 against the Pentium III 1266S's 210 — a 7.4% lead for the Pentium III 1266S. Both processors carry 0 kB of L3 cache.

Feature	Atom Z515	Pentium III 1266S
Cores / Threads	1 / 1	1 / 1
Boost Clock	1.2 GHz	1.27 GHz+6%
Base Clock	1.2 GHz	—
L3 Cache	0 kB	0 kB
L2 Cache	512 kB (per core)	512 kB
Process	45 nm-65%	130 nm
Architecture	Silverthorne (2008−2010)	Tualatin (2000−2002)
PassMark	195	210+8%

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Memory & Platform

The Atom Z515 uses the PBGA441 socket (PCIe 2.0), while the Pentium III 1266S uses PGA370 (PCIe 1.1) — making them incompatible on the same motherboard.