Internet Speed slower than advertised
I had the Premiere Internet speed (150 mbps download and 10 mbps upload) before switching to Ultimate (300 mbps download and 20 mbps upload speeds). The Ultimate was bundled with Contour TV and Homelife that's why I decided to get this deal. I was getting between 120-140 mbps with my old internet speed, I use both COX speed test tool and speedtest.net they show really close results. When I switched to the higher speed I was only getting speeds between 150-170mbps using the same tools. I called COX and told them what was going on. The rep said that on their side it shows that I have the fastest internet speed but no way to check my speed and couldn't give me answer why it is slower than what I'm paying for. The rep then said it could be my computer, it may not able to handle the "speed". I told her that my pc is still brand new (I built it in December 2016). I also checked my internet speed using my 6-year old pc and I get the same speed about 168 mbps. When I tested my speed both computers are hard wired. Is this pretty normal for other customers? Why would Cox advertised high speed internet but when I check it I only get just a little over half of the speed?
This is my computer specs:
CPU: Intel Core i5 6600k
RAM: 16GB
Video: Nvidia gtx 1070
SSD: 240GB Kingston
Modem: DOCSIS 3.0 Netgear Cable Modem CM600
WIFI Router: Netgear Nighthawk AC3200