I have 2 Toshiba Satellite computers about 6' apart in the same room sharing a home wireless network. One has acceptable internet speeds but the other is very slow. Both systems indicate excellent signal quality, but the connection status indicates a speed varying from 18 Mbps to 36 Mbps on the faster system and a speed seemingly fixed at 18 Mbps on the slower one. Both use similar Realtec wireless adapters with identical settings in advanced properties. An exhaustive search for malware on the slow system found no issues. Turning the fast computer off completely did not improve the speed on the slow one. Deleting temporary internet files and trying alternative browsers did not resolve the issue.
Since my wife is begrudgingly using the slower computer, I've got to figure this out so she'll keep me around a bit longer.
The key description here being that the slower one you said is fixed at 18gbs and the other one varies. So that means there is something making the speed fixed and it has to be a setting someplace either in the wireless router or in the adaptor on the laptop.
(SOLVED) When I ran speedtest.net, I found that the download speed was only about 5 Mbps. Speed was very close to 15 Mbps when connected with ethernet. The problem was the simplest one...degradation of the wireless signal quality. When I moved the "slow" laptop nearer to the router, speeds improved significantly. I was following the wrong track because I could not see why the speeds of 2 computers so close to each other would be so different...but they were.