Speed Test Shows Only One Line Speed After Combining Connections
You set up two lines, opened a speed test with full hope — and the result is the same single-line speed as before. Before you undo everything, read this: in most setups that result is exactly what the technology is supposed to produce.
✍️ Technical Anshu🪟 Windows 10 / 11⏱️ 8 minute read
🎥 Watch the full process in the video — combining 2 connections with real testing, step-by-step
This is the most common disappointment after combining two connections, and it is almost never a fault. Load balancing works per session. Each connection a device opens is placed on one line and stays there. A speed test is just another set of sessions, and depending on how the test runs, it can easily sit entirely on one WAN. Here is how to tell a healthy setup apart from a real problem.
Same setup, two different test styles — example values
Single connection test24.8 Mbps
Multi connection test34.6 Mbps
Two devices testing together34.1 Mbps
One test style uses only one line — the multi-connection styles reveal the combined total
1
Why the Test Lands on One Line
A load balancer decides the path when a session starts. A quick speed test may open all its streams to one test server within a moment, and the router can place them all on WAN1 — especially when the balancing works per destination or per session burst. The test then truthfully reports the speed of one line, while the second line simply had nothing to carry.
There is a second, sneakier cause, and it is the one in the video: many ISPs cap speed per connection, not per line. A 250 Mbps line that gives only 25 Mbps to one download is not broken — the cap is per flow. Ten flows would get far more in total, which is precisely the problem combining is meant to solve.
2
Test in Multi-Connection Mode
In your speed test app or site settings, look for Connections: Single / Multi and choose Multi
Run the test again — a multi test opens many parallel streams, which the balancer spreads across both WANs
Compare honestly: single mode shows your worst-case single download; multi mode shows your network's total capacity
Neither number is fake. They answer two different questions, and for judging a combined setup, the multi number is the right one.
3
Watch the Router, Not Just the Test
The most reliable proof is the router's own live traffic screen:
Open the router admin page and find Status / Traffic Monitor with per-WAN graphs
Start a big multi-connection download (a download manager set to 16-32 connections is ideal)
Both WAN graphs should rise together — if they do, combining is working, whatever any single test said
You can also run ping 8.8.8.8 -t in one window while downloads run; stable replies mean neither line is choking.
4
When It Really Is a Fault — Check These
Mode set to Failover: WAN2 stays idle until WAN1 dies. Change to Load Balance if you want both active
Second WAN not actually connected: check its status, IP address and PPPoE login on the router
Weights badly skewed: a 95 : 5 ratio makes line 2 nearly invisible in tests
Testing over weak Wi-Fi: a slow wireless link can cap below one line's speed — test with a cable
One PC, one adapter: without a dual-WAN router, a single Windows PC uses one default route — see the core guide
Work through this list before blaming the concept; in practice the mode setting is the culprit in most 'not working' reports.
🔴 A single-connection speed test cannot prove a combined setup is broken. Judge combining by total throughput across many sessions — multi-connection tests, parallel downloads, or the router's own per-WAN traffic graphs.
🎥 Watch the Complete Video Guide
Watch the video to see the real office lines, the per-connection cap problem, and how the combined speed was actually measured.
My speed test shows exactly the same speed as before combining. Is the router faulty?
Almost certainly not. Most likely the test's sessions all travelled on one line, which is normal load-balancing behaviour. Run the test in multi-connection mode, or start two large downloads at once, and check the router's per-WAN traffic graph — that shows the true combined total.
Why does my 250 Mbps line give only 25 Mbps on downloads?
Many ISPs, especially on leased and shared business lines, limit speed per connection rather than per line. One flow gets a slice; many parallel flows together can use much more. A download manager with 16-32 connections, behind a load balancer, is the standard way to use that headroom.
Can I force the speed test itself to use both lines?
Only by choosing the test's multi-connection mode, if it offers one. You cannot force a single session to split across two lines with a load balancer — that requires true bonding, which combines streams through an external server.
This guide is based on the Technical Anshu video on combining 2 LAN connections • Stuck on a step? Ask in the video comments — the community helps there 🙏