<p>My company is just starting to look at using WPF for migrating all of our 10 year old business applications. These applications will most of the time be running on computers that have limited/old hardware. We are now a little worried that the hardware might be too limited for using WPF. </p>

<p>We have installed Family.Show (<a href="http://www.vertigo.com/familyshow.aspx" rel="noreferrer">http://www.vertigo.com/familyshow.aspx</a>) on an basic older computer and that seems to run ok. But we would like know what your experiences with WPF on older hardware is? Anyone out there willing to share some experiences with us?</p>

WPF apps will
generally
run no slower than their equivalents using other technologies. In other words, performance depends on what you're doing. If you have a basic app with some simple data entry controls and a grid or two then it'll be a lot less demanding than an app that has animated custom controls with overlaid video, etc.
You should also bear in mind that you must have at least XP SP2 to install WPF, which sets a reasonable hardware baseline anyway.
In summary you should have no problems running a WPF app on older hardware as long as you are sensible with the frills. Given WPF's templated controls it's also fairly trivial to test for a basic level of client performance at runtime (see
Graphics Rendering Tiers
) and only enable more advanced features on suitable hardware.