OK, we have 2 different kinds of those DVB-T things.
My laptop is a pretty good spec and running well (I am a computer engineer).
I have given up with them and bought a very nice Bush 19" TV with HD, a DVD player and freeveiw all built in for £99. ( like this =
http://www.ebay.co.uk/itm/12-Volt-Bush- ... 19cb7d6c8e" onclick="window.open(this.href);return false; ) Note = you need to buy a separate power lead for that one, or do as I did and chop the low voltage lead off from the power supply and splice onto a 12 V feed (+ve is the centre core of the cable).
Reasons =
Those USB things are a faff (imho) it takes an age to do the "search for channels" and you have to do it every time you go to a different location. (I know you do this with the TV too, but it only takes a couple on minutes).
The little aerial that comes with them is only of use if you can pretty much SEE the transmitter with your eyes !
Then the picture quality is poor when it does work, and the lip sync often drifts away !!
I use (with the USB thing and the new TV) a non powered indoor TV aerial with 4 magnets glued to the bottom to make it stick on the roof. (Non powered because it does not matter if it gets wet). On the Hi-Top I find the aerial works fine inside the roof because it ain't metal
With all the advantages I get with the great TV @ £99 I wouldn't go back to the USB TV dongle thing !