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IIS vs Windows Server

Based on 80 and 79 real audits

MetricIISWindows ServerWinner
Performance5051Windows Server
Accessibility8888Tie
Best Practices8687Windows Server
SEO9192Windows Server
Security6869Windows Server
TTFB519ms530msIIS
Composite7474Tie
Performance
IIS
50
Windows Server
51
Accessibility
IIS
88
Windows Server
88
Security
IIS
68
Windows Server
69
SEO
IIS
91
Windows Server
92
Composite
IIS
74
Windows Server
74

Windows Server outperforms IIS in 4 of 7 categories, with a stronger composite score (74 vs 74). 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 performance and best practices. Its audit data shows consistent strength in these areas across the sampled sites.

How this comparison was built

Scores are medians across 80 audited IIS sites and 79 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, Windows Server sites score higher on Lighthouse performance (51 vs 50 on average).
Which has better security, IIS or Windows Server?
Windows Server sites score higher on security analysis (69 vs 68 on average).
Which has better accessibility, IIS or Windows Server?
Accessibility scores measured by Lighthouse WCAG 2.1 checks favor IIS (88 vs 88). 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 (92 vs 91 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 (519 ms vs 530 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. Windows Server 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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