Even a old piece of junk will be faster than the any internet connection. Even if you use all equipment limited to 100m you are still well beyond any internet speed you can buy. You might get 50m on a good system in bursts.
One of the few internet application that do need high power machines are games, most everything else is limited by the network connection before the PC has any effect.
If you are talking about real computer based trading where fractions of a second make a difference you cannot use internet you must be on the trading network.... cost lots of money.
If consideration were given to cpu speed, memory size, operating system, etc., which of these would offer the greatest contribution to internet access speed? Which would be the second?
I have a collection of mainboards, ethernet cards, and most of the windows operating systems and I want to assemble a system that will let me do the fastest online stock trading. I will be using a broadband cable connection.
Thank you for any advice.