Couldnt find the forum for the 635 so i guess this is the next best place to post my problem.
I just upgraded my old Linksys for the DIR 635 and i have it setup and it seems to work nice apart from one issue, i removed my old router because it suddenly started to have speed/stability issues and this one is fine but i have a small stability issue.
For example if i download from my ISP FTP or a newgroup its all good and i get a stable 1Mbps but then all of a sudden the speed halfs or even goes down to 100kbs, this can last 1 min or two mins maybe more and its rather anoying as this router cost close on £100 and i was expecting more than this.
I disabled QOS / Traffic shareing incase that was causing it but i am the only connection on the line currently and the issue still persists.