Here are just a few things to try to do to narrow down what the problem could be:
1. Save the Configuration. Do that first and foremost. Don't want to experiment and end up making it worst.
2. Bypass the router and go direct to set a control at that particular moment. Could be your testing direct at night, and router by day, and giving you a false negative. **Also* check what your DNS servers are direct to modem and write them down.
3. Reconnect the router and go hardwired using the same computer you tested wired on. If slower, continue on, if the same, no problem found.
4. Disable Gamefuel. Save settings, try the test again. If faster problem found, if slower, re-enable it and continue to next step.
5. Disable advanced DNS(If not enabled, skip this step). Save settings and run the test again. If no change re-enable and continue.
6. Disable DNS relay and manually fill in your DNS addresses. Save settings and test.
7. Make sure any AV is turned off. Alot of times when a new connection is tested, it can be given different security settings that effect testing. Norton/Mcafee are the two biggest culprits of this.
If you don't know how to do some/all of these tests, respond and I will break them down specifically. Good luck.