Your Internet Cable Service may be running at Half Speed
About 18 months ago I started receiving email notices from my internet cable service provider which mentioned that download speeds had been increased to 6.0Mbts. Being excited about this I decided to check my actual speed by using one of many web sites that test and report your speed. To my surprise my speed had actually gone down and not up. The best numbers I could get at any time of the day or night where about 2.2Mbts (Mega Bits Per Second), which is about one third of the advertised speed. Iíll include a list of several test sites at the bottom of this article.
So I called Tech. Support and explained the situation. The technician then checked my cable modem from his remote location and found that I had far too much signal strength at the input to the cable modem and scheduled a service call.
The technician showed up on time the next day and replaced the cable running from the line strung between the two poles to the point where it enters my house. He also replaced the splitter which is used to provide a separate line for cable TV. Another check of the signal strength showed it was now even higher and further out of specification than before. There was no increase in cable speed. A second service visit was scheduled.
On the second visit another tech. replaced the signal attenuator on the telephone pole to reduce the amount of signal down to a value that was within their guidelines and also found a broken box located two telephone poles before my house. Still no speed increase. The technician did notice that I had an old modem and scheduled for a replacement to be installed.
On arrival the third technician looked up the model (DOXport 1110) of my current modem and found that it was obsolete and no longer supported. This was the modem that was installed when I first subscribed more than 4 years ago. The new modem (Motorola SB5120) he installed was defective and had to go out to the truck to bring in another modem. This was an older model (SB4200) than the modem that was defective but still newer that my original modem. A speed test showed about a 50% increase to 3.0Mbts.
Next we disabled my firewall (Zone Alarm), Anti-Virus software and other Anti-Spyware software I had running in the background. With everything disabled there was no increase in speed which at least showed these utilities were not the problem. Note that some earlier versions of Zone Alarm can cause a speed problem so you should update to the latest version of the freeware or paid version. We then bypassed my router and connected the output of the cable modem directly into the input of my network card, still no speed gain.
The tech. then connected his laptop to the new modem and instantly got a speed increase to about 4.0Mbts. Could it be my PC or some software that was the problem?
I wasnít satisfied with the current state of things and a friend of mine had an extra and newer model (SB5100) of the Motorola modem installed by the technician, so I asked Bill to drop it off.
Read on for the answer:
The next day I called the cable companies tech. support department and together we tested my existing modem and then installed the Motorola SB5100 modem. Bingo, speed was now up to 4.2Mbts, definitely an improvement but still not 6.0Mbts as advertised.
Now I remembered some old tricks that use to work for Windows 98, but not for Windows XP. Still I searched the web and found a simple utility named Dr. TCP provided the final boost in speed. Using this utility I found that my TCP Receive Window was not set to any value, so I entered a value of 56940, leaving all other fields in this utility unchanged.
No reboot of your PC is necessary so I immediately checked my speed again and found I was now up to 5.0Mbts or more on a consistent basis. Keeping in mind that 6Mbts is a theoretical maximum under ideal conditions and finding that values greater than 56940 did not improve my speed I decided that a 250% speed improvement was not bad at all.
Just the other day I had a need to download a file that was more than 200Mega Bytes in size. My download speed was above 700KBts per second (5.6Mbts) from this web site.
My web pages now load noticeably faster, more importantly large file download times are more than twice as fast. Over time my download speeds increased to 6.5Mbps, but I recently decided to go with another ISP.
In May of 2008 I switched from Cable to Fiber Optic Service (FIOS) which is capable of downloading files almost 3 times faster (18.5Mbps) than my former cable Internet Service Provider.