Video buffering? Web pages loading at a crawl? Let’s track down the bottleneck and fix it. The key is measuring your speed first, then eliminating causes one at a time.
Measure Your Current Speed
“Slow” is subjective. Get numbers first. Try Google “speed test” (built-in test in search results), Fast.com (Netflix’s simple tool), or a local Japanese speed test service. Run it three times under the same conditions and average the results. Test at different times of day to spot congestion patterns.
Reading the Results
Three numbers matter:
- Download speed: for browsing and video streaming
- Upload speed: for Zoom calls and file transfers
- Latency (ping): for gaming and video calls responsiveness
A download speed of 30 Mbps handles 4K video comfortably. 10 Mbps is fine for YouTube. Ping under 20 ms is excellent; over 100 ms means noticeable lag in online games.
Find Bandwidth Hogs
Check your router’s admin panel to see which devices are consuming the most bandwidth. Common culprits: 4K streaming (up to 25 Mbps per stream), game console updates (massive downloads), phone photo backups, and IP cameras or smart home devices that communicate constantly.
If your network slows down at the same time every day, look for a scheduled backup or update running in that window.
Reduce Signal Interference
Physical Interference
- Keep the router away from walls and metal furniture
- Microwaves operate on 2.4 GHz and can disrupt Wi-Fi while running
- USB 3.0 devices and Bluetooth gadgets can interfere with 2.4 GHz
Channel Interference
Use a tool like Wi-Fi Analyzer to see which channels your neighbors are using. Switch your router to a less congested channel. For 2.4 GHz, stick to channels 1, 6, or 11 (they don’t overlap).
Go Wired When Possible
Nothing beats an Ethernet cable. Connect stationary devices like TVs, game consoles (PS5, Switch), and desktop PCs via LAN. If you can’t run cables, don’t worry — wireless is fine for mobile devices.
Extenders vs. Mesh vs. Powerline
| Solution | Pros | Cons |
|---|---|---|
| Range extender | Cheap (from ¥3,000) | Cuts speed in half |
| Mesh Wi-Fi | Seamless whole-home coverage | More expensive |
| Powerline adapter | Uses electrical wiring | Works best on same circuit |
Budget mesh kits like Amazon Eero or TP-Link Deco are popular and can cover a whole house for around ¥50,000.
Check Your ISP Plan
If you’ve optimized everything and it’s still slow, your internet plan may be the bottleneck. Know your plan’s maximum speed. Real-world speed is typically 30–50% of the advertised maximum. IPv6 (IPoE) connections tend to be more stable. If evenings are always congested, your provider may be oversubscribed; switching could help.
Summary
The order of operations: router placement → channel selection → wired connections → hardware upgrades → ISP plan review. Before buying a new router, try the free fixes first.