Sorry but Avalon is quite correct (as usual). Virgin Media removed all downstream and upstream throttling and management on all products recently. If you're seeing slow-downs look at your local network first. Did you reboot your SuperHub lately? The service itself may be uncapped but the SH has a nasty habit of falling over if not rebooted every week or thereabouts. Local congestion can also obviously play a role.
ETA: I download a couple of TB (terabytes) a month at least, and VM never slow me down. The only time my speed dips is between around 7pm and midnight on a weekend or bank holiday, and that's just local congestion. Even then I'm still seeing 200 to 250 Mbps down. Certainly no correlation to download volume, as I pull down many GB throughout the day at full speed without issues.
ETA: I download a couple of TB (terabytes) a month at least, and VM never slow me down. The only time my speed dips is between around 7pm and midnight on a weekend or bank holiday, and that's just local congestion. Even then I'm still seeing 200 to 250 Mbps down. Certainly no correlation to download volume, as I pull down many GB throughout the day at full speed without issues.