This is a difference in running between screensaver and normal mode. Firstly, you will only be crunching when the screensaver kicks in. Secondaly, your PC will waste a few cycles showing the pretty picture in screensave mode.

What a lot of us do is to run the client all the time. Don't worry about it getting in the way of other work. It is configured to run at the lowest priority and step away when other programs need processing power.

The other thing that we do is to switch the screensaver to blank and modify the power saving setting to ensure that the machine does not go into standby/hibernate. This way, the machine can keep crunching through the night.

If you are thinking of getting a dual core machine, you will only be able to run one instance of the client as mycroft says. If you have the time/money, you could run something such as VMware and run a second instance in a virtual machine and allocate on processor to the real machine and one to the virtual machine.

That is not entirely correct. If you have a PC with 2 processors (like the new duel core CPUs that Intel and AMD have recently released), most distributed computing projects will allow you to setup 2 clients on the same PC (one for each core) and the clients will work on 2 different workunits at the same time. You will then return twice as much work.

G