I am currently running Windows 7 with FIOS Internet running at a speed of 25/25.
Immediately after installation my speed was only 17.5/20. The tech who installed the FIOS, while on site at my house, could not figure out why it would not reach full speed. I checked numerous forums and tried everything under the sun, with no success.
I ran my PC in Safe Mode, brought up Task Manager, and took a screenprint of the processes running. I then rebooted normally. I brought up Task Manager again and compared the currently running processes to the screenprint of the processes running in Safe Mode.
The main difference was that my anti-virus/malware software does not show up in processes in Task Manager in Safe Mode. Disabling or stopping those services will not fix the issue. YOU HAVE TO COMPLETELY REMOVE YOUR ANTIVIRUS SOFTWARE/MALWARE.
I did this and made sure there were no traces left. I ran CClenaer as well to remove any registry entries leftover.
After running a speedtest to check the speed of the connection, SUCCESS!!! Speed was a full 25/25 !!!! I ran different speedtests at different times during the day and on different days. Still a solid 25/25!
I don't want to single out the anti-virus company as it may just be a simple incompatibility issue, but I was running AVG free edition. I installed a few other anti-virus programs to see if it would reduce the speed again. It did not. Just pick one you think is good and see if it affects the speed.
The funny thing is is that no forum I checked (of course I did not check every one) as well as the Verizon tech and their customer service tech line never mentioned anything about Anti-Virus software being the culprit. Strange, Anyway, I hope this sloved your issue. Post your results if you can. Thanks.