| Metric | IIS | Windows Server | Winner |
|---|---|---|---|
| Performance | 45 | 45 | Tie |
| Accessibility | 87 | 87 | Tie |
| Best Practices | 84 | 85 | Windows Server |
| SEO | 90 | 91 | Windows Server |
| Security | 66 | 66 | Tie |
| TTFB | 513ms | 527ms | IIS |
| Composite | 72 | 72 | Tie |
Windows Server outperforms IIS in 2 of 7 categories, with a stronger composite score (72 vs 72). IIS leads in TTFB.
Choose IIS when your primary concern is server response time. Its audit data shows consistent strength in these areas across the sampled sites.
Choose Windows Server when your primary concern is best practices and SEO. Its audit data shows consistent strength in these areas across the sampled sites.
Scores are medians across 66 audited IIS sites and 65 audited Windows Server sites in the BeaverCheck database. Every audit runs the same 100+ checks — Lighthouse performance, security headers, accessibility, SEO, server response time — against a real URL. No vendor input, no sponsorship, no affiliate links. Read the full methodology →
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