Data Transfer Rates
and How They Affect Web Page Load Times

 

Why do some websites load more slowly than others?

Can websites cause computers to crash?

What can the end user do to improve load times?

How can I minimize the load time of my website?

 

Table of Data Transfer Rates

 

 



Why do some websites load more slowly than others?

A website can load slowly for a variety of reasons. Lots of code within the web page itself, lots of images, images with large file sizes, graphics with large file sizes, they are all possible causes for why a web page might load slow. So are bad phone lines, hardware and/or software problems, line congestion and/or collapse. However, the most important and common of causes is the technology in use. Sometimes the obvious escapes us, and in this case, a very obvious example to point out is the difference between working with a modem and a T1 or E1 connection. Of course, if we add a bad line connection to the fact that we are working with a modem, the reason why a website loads slowly becomes even more "obvious". See the Table of Data Transfer Rates for a comparison of the main technologies in use today.

Back to the top

Can websites cause computers to crash?

Normally websites do not cause client computers to hang. What happens is that sometimes it looks as though they have temporarily crashed because the CPU is completely occupied with the task at hand. Nevertheless, the computer hasn't crashed and there are signs -- like the blinking lights from the telephone connection icon, the messages in the status bar, and the LED on the NIC if you are connected to a LAN -- that clearly indicate that the computer continues to work fine.

Back to the top

What can the end user do to improve load times?

In a word, the end user should be patient and let the web page load to avoid further complications. In any event, if you are working with a slow connection and low speed technology, the situation is not as bad as it might sound since your computer saves a local copy of all the web pages you visit. This means that in 'real terms' your patience is only going to be tested once because, with every visit after the first visit, the copy is loaded and a complete retransmission of data isn't necessary.

Back to the top

How can I minimize the load time of my website?

The short and simple answer is that you can minimize the load time with optimization, but things are never that simple. Here we enter into world of trade-offs. For example, if you wanted a website that exhibited your photography, you would have to find the trade-off between high quality images and small file sizes. The better the quality, the larger the file size, and that translates into longer load times (slower loading web pages) given that there are more bits to be transmitted across the wire. Like the photography website example, a portal website is going to take longer to load due to the simple fact that it contains a lot of information. If the website is going to have a lot of information, you will have to limit that information to that which is absolutely necessary so that the file sizes of the pages are as small as possible. In both cases we have to sacrifice either quality or information if we want to get the files sizes down so that the web page loads more quickly. It is also important to keep in mind the website visitor and their goals. For example, end users will wait longer to enter a portal (knowing that once inside they will find lots of useful information) than they will to see a personal website. In short, every effort should be made to minimize long load times, but the task of achieving good, appropriate optimizing in function of the type of website, its target audience, etc., is far from simple.

Back to the top


Table of Data Transfer Rates

Type of Connection -
Technology Used

Maximum Speed *

Time Necessary to
Load GaliciaWeb **

14.4 modem
14,400 bps
58 seconds
28.8 modem
28,800 bps
29 seconds
33.3 modem
33,300 bps
25 seconds
56k modem
56,000 bps
15 seconds
ISDN
128,000 bps
6.5 second
ADSL
256,000 bps
3.25 seconds
T1 Line
1,544,000 bps
0.54 seconds
E1 Line
2,048,000 bps
0.41 seconds


* Maximum speed assumes an idealized transfer rate, that is to say, the theoretical bandwidth -- the maximum theoretical throughput permitted by the media -- that can be transmitted through the media in perfect conditions. (Needless to say, those perfect conditions never exist. There are always factors that cause the real transfer rate to be less than the theoretical and that leave us with what is called actual throughput. A bad phone line is something that all remote users have experienced at one time or another. Saturated bandwidth, hardware limitations and plane old physics are some other factors that cause throughput to fall and move away from those theoretical data transfer rates.)

** This is the time that it takes to load the home page of the English version of GaliciaWeb, and, once again, it assumes a perfect connection between connecting devices that achieves maximum theoretical transfer rates. The real data transfer rate will always be at best a bit lower, and at worst, quite a bit lower.

Back to the top

Close this page