4 gig is pointless as XP and Vista 32 bit can only address slightly more than 3 Gb. Your 2Gb for a dual core is more than sufficient. See the System Requirements in Help for the resources PER running science and multiply by X cores to find the maximum usages.

Interesting: Build date: 1/15/2009 though it does not specify the definition of physical and virtual.

Some motherboards only have two memory slots, so two 2 Gb sticks is a common configuration for 32bit systems.

More memory wouldn't make a whole lot of difference for a pure cruncher, but it certainly helped the multitasking for my desktops, which have 4 Gb of memory, and often have other things going on as well. The difference between 2 Gb and 4 Gb was very noticeable.

Well, after all these posts in six minutes you are probably as uncertain as before!
There is another option if you are ready to buy 2 gigs of RAM. If the RAM that Dell has generously offered you in this machine is not the fastest that your BIOS can manage and if 2 gigs are enough you might simply replace the original ones with better ones and then crunching speed should really improve, which seems to be your first motivation. But don't simply add them because they would adapt their speed to that of the slowest one.

Good luck. Jean.

You should also consider the RAM timings. You will generally see this referred to as CAS or latency. This is the amount of time the chips need to respond to a command (the time for each type of command sometimes varies but is usually the same as the CAS number)

Wikipedia has a decent explanation.

Take a look at the chart they provide and you'll see that DDR2 memory running at 400mhz but with a 2 cycle latency is almost as fast (27.5 ns) at moving 8 words of data as DDR2 800mhz with CAS 6 latency (23.75ns) - - even though you would assume that DDR2 800 would be twice as fast!

So if you replace your memory with DDR2 chips that have both a higher clock rate (800mhz, 1066mhz, etc) and lower latency (CAS 2, CAS 3, etc) you should notice the difference.

However since WCG is CPU intensive - i.e., does not require huge amounts of memory access (like say, video encoding) - I don't know how much of an improvement you will see. I'm sure there will be some, but I doubt it will be dramatic.

Additional and faster memory (higher speed, lower latency) will however make your computing experience much more pleasant. That much I can guarantee.