Please allow me to better explain my needs for this main computer: I am an Astronomer and this machine I'm working on now is the main one that processes my images. The other one that I wanted to upgrade is the one that operates the telescope and it's imaging software.
So to explain the use of this main machine, consider the way AstroPhotography works in this brief explanation: The CCD camera on the telescope shoots multiple images (50-150 depending on the object) of the object as the telescope follows it across the sky. Since no telescope can PERFECTLY track an object, the object appears in a slightly different location in each of the perhaps 150 images that the CCD camera takes.
Special astro software is used to stack these pictures. Each one is 1200x1600 and is 8.3MB in size. Stacking them requires the software to track as many of the stars in the field of view as possible, and move each picture slightly to match the position of the one before it. You can picture what it takes for the software to scan pictures that large for stars, then superimpose those stars on each other 150 times.
This is done three times for each color image. One stack for RED, one for BLUE, and one for GREEN. Finally the resulting three RGB files are themselves stacked in Photoshop CS4 to produce a color image (each of the three individual components is a grayscale image). Special astronomy actions for Photoshop do the final processing on these color images and they may have 10 layers or so which can mean I'm processing an image that is about 25MB in size.
So you can see, that if I use the telescope to shoot images of say, 6 or 10 different objects on a good night, the next day is spent doing a lot of image processing. That is the main function of this computer. FYI examples of my AstroPhotography can be found
here at this link. That site has a hundred or so images that I have processed of different objects, most of them in color using the above procedure.
The other computer that actually runs the telescope and it's associated software, is the one that I used the Pentium-D chip in. It is outdated and needs a better processor, now that updated versions of the software are requiring more horsepower. That's why I figured I would donate this chip which is already a quad-core.
I hope this makes sense. And remarks on my photography are always welcome too!