Before I hooked up my router (a Linksys BEFSR41 v2) I used to get speeds of 1500-1800k. Ever since I installed it I have been getting speeds anywhere between 500 & 700k. I have tried hooking the modem directly up to my computer and my speeds shoot right back up to where they should be. All I have connected to router are one PC and my XBOX. Any ideas as to why my speeds are down to less than half?