What DNS Does (and Doesn't Do)
When you type a URL, your device first contacts a DNS server to find the IP address of that server. This lookup happens before any actual data transfer begins. A slow DNS server adds a delay to every new connection—not to ongoing transfers, but to the initial handshake for each new website, image, API call, or resource your browser loads.
Changing DNS does not increase your download speed, lower your ping to game servers, or fix ISP congestion. What it can do is reduce the time-to-first-byte for web browsing, which makes pages feel more responsive even if the data transfer speed is unchanged.
Popular DNS Servers Compared
| DNS Provider | Primary | Secondary | Privacy | Speed (Global Avg) |
|---|---|---|---|---|
| Cloudflare | 1.1.1.1 | 1.0.0.1 | Strong (no 24h+ logs) | Fastest globally |
| 8.8.8.8 | 8.8.4.4 | Moderate (collects analytics) | Very fast | |
| Quad9 | 9.9.9.9 | 149.112.112.112 | Strong + malware blocking | Fast |
| OpenDNS | 208.67.222.222 | 208.67.220.220 | Moderate (owned by Cisco) | Fast |
| Your ISP's DNS | Assigned automatically | — | Weakest | Variable—may be fastest locally |
How Much Difference Does It Make?
In controlled tests, the difference between a fast DNS (1.1.1.1) and a slow ISP DNS can range from 10ms to over 100ms per lookup. For a page that makes 20 separate resource requests, a 50ms DNS improvement per request would save 1 second of total load time—noticeable but not transformative.
The benefit is most pronounced if your ISP's DNS servers are poorly maintained, located far from you, or overloaded during peak hours. Some smaller ISPs have notably slow DNS infrastructure. The best way to know if switching will help is to test before and after using a tool like DNS Benchmark (Windows) or dnsperftest.sh (Linux/Mac).
How to Find the Fastest DNS for Your Location
Global averages don't always predict local performance. DNS response time depends on the route between you and the server. Here's how to benchmark:
- Windows: Download DNS Benchmark by GRC (free). Run it to test 70+ DNS servers and rank them by response time from your connection.
- Mac/Linux: Use the command
time dig @1.1.1.1 example.comand replace the IP to compare different servers. - Any device: Use the online tool at dnsperf.com to see current benchmarks by region.
How to Change DNS on Your Router
Changing DNS on your router applies to all devices automatically. Log into your router admin panel (usually 192.168.1.1 or 192.168.0.1), find the DNS or WAN settings, and enter the primary and secondary DNS server addresses. Save and apply. Your devices will pick up the new DNS settings when they renew their DHCP lease—rebooting devices speeds this up.
DNS Over HTTPS (DoH)
Traditional DNS queries are unencrypted—your ISP can see every domain you look up. DNS over HTTPS (DoH) encrypts DNS queries so they're indistinguishable from regular web traffic. Both Cloudflare and Google support DoH. Browsers like Firefox and Chrome can be configured to use DoH directly, independent of your system DNS settings. This is the best option for privacy if you're on a network you don't control (public Wi-Fi, work networks).
Frequently Asked Questions
Does changing DNS actually improve internet speed?
DNS affects how quickly domain names are resolved—it doesn't change raw download or upload throughput. The benefit is in page load times: a slow DNS server adds 50–200ms to every new connection. If your ISP's DNS resolvers are slow or overloaded, switching to 1.1.1.1 or 8.8.8.8 can noticeably speed up browsing without changing your internet plan.
What are the fastest DNS servers?
In global average latency tests, Cloudflare's 1.1.1.1 consistently ranks fastest, followed closely by Google's 8.8.8.8. However, the fastest DNS server for you depends on your geographic location and ISP routing—your ISP's own DNS may actually be fastest if well-maintained and geographically close.
What is the difference between 1.1.1.1 and 8.8.8.8?
Both are fast, reliable public DNS resolvers. Cloudflare's 1.1.1.1 is typically slightly faster and has a stronger privacy policy. Google's 8.8.8.8 has a larger global infrastructure but does collect DNS query data for analytics. For pure privacy, 1.1.1.1 is preferred.
Should I change DNS on my router or on each device?
Changing DNS on your router applies to every device automatically—it's the more efficient approach. Change it per-device only if you want different DNS settings for specific devices.
Can changing DNS bypass ISP throttling?
Not typically. DNS controls name resolution only. However, if your ISP uses DNS-based filtering to block specific sites, switching to a public DNS can bypass that. For bandwidth throttling, a VPN is more effective.