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IIS vs Windows Server

Based on 66 and 65 real audits

MetricIISWindows ServerWinner
Performance4545Tie
Accessibility8787Tie
Best Practices8485Windows Server
SEO9091Windows Server
Security6666Tie
TTFB513ms527msIIS
Composite7272Tie
Performance
IIS
45
Windows Server
45
Accessibility
IIS
87
Windows Server
87
Security
IIS
66
Windows Server
66
SEO
IIS
90
Windows Server
91
Composite
IIS
72
Windows Server
72

Windows Server outperforms IIS in 2 of 7 categories, with a stronger composite score (72 vs 72). IIS leads in TTFB.

When to choose IIS

Choose IIS when your primary concern is server response time. Its audit data shows consistent strength in these areas across the sampled sites.

When to choose Windows Server

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.

How this comparison was built

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 →

FAQ

Which is faster, IIS or Windows Server?
Based on real BeaverCheck audits, IIS sites score higher on Lighthouse performance (45 vs 45 on average).
Which has better security, IIS or Windows Server?
IIS sites score higher on security analysis (66 vs 66 on average).
Which has better accessibility, IIS or Windows Server?
Accessibility scores measured by Lighthouse WCAG 2.1 checks favor IIS (87 vs 87). Both technologies can be made fully accessible with care — the difference reflects common patterns in the sampled sites, not inherent platform limits.
Which is better for SEO, IIS or Windows Server?
Windows Server sites score higher on Lighthouse SEO signals (91 vs 90 on average), which cover meta tags, crawlability, mobile friendliness, and structured data. Content strategy and backlinks still matter more than platform choice for ranking.
Which has faster server response (TTFB), IIS or Windows Server?
IIS sites show lower Time to First Byte (513 ms vs 527 ms on average). TTFB depends heavily on hosting and CDN setup rather than the technology itself, but the sampled sites suggest a meaningful difference in common deployment patterns.
Should I choose IIS or Windows Server for my website?
Both platforms have trade-offs. IIS scores higher on overall composite score while IIS may excel in metrics you care about most. Run a free BeaverCheck audit on a real site using each to compare the metrics relevant to your use case.

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