The "best" option is this one: 4GB, 800MHz, DDR2 SDRAM Memory, ECC (2 DIMMS) [add $550] However, that price is absurd. Two 2GB sticks of the absolute best DDR2 can be had for under $150 (that's under $150 total for the 4GB) from any number of computer part retailers. Looks like Dell bought too much DDR2 before prices plunged six months ago and is trying to unload it on people who aren't aware. Go for the cheapest memory option they offer, and upgrade the memory yourself.
Bear in mind that 32 bit operating system (e.g. XP and Vista 32 bit version) can only utilize up to 3 GB of memory. That's why... Dell recommends 2GB memory for greatest productivity 99% of the popular trading environment on the market uses less than 1GB of memory. With XP, even if you have opened your web browser, Skype, Excel, Word, MSN, etc., you will not consume more than 1.3GB of memory. Can't say the same for Vista though; Vista uses a lot more memory than XP.
The fastest Dual core CPU right now is the Intel Core2Duo E8500. They are still new, and is not easy to come by. You can see Tom's Hardware chart below for comparison. I chose PCMark2005 CPU because it is not multi-core optimized. http://www23.tomshardware.com/cpu_2007.html?modelx=33&model1=1098&model2=946&chart=416 <img src="http://www.elitetrader.com/vb/attachment.php?s=&postid=1813920">
p.s. How many of these Single-Threaded applications you are running? If you run more than one instance of the program, each instance can use its own core in a multi-core CPU. A quad-core will still be faster than a dual-core set up if you run more than 2 programs at the same time.
Picked out a case... it is the Elite by Cooler Master. Can you find a more fitting case for an Elite Trader Project ? <img src="http://www.elitetrader.com/vb/attachment.php?s=&postid=1814263">
This is a Mid-Tower case, measuring (W)203 x (H)413 x (W)486 mm. http://www.coolermaster.com/products/product.php?act=detail&tbcate=168&id=187 The case has a CPU fan air duct, which is essential for my Quad-core CPU. The drive bays and expansion slots are of tool-less design. i.e. I do not need a screw driver to add/extract components. <img src="http://www.elitetrader.com/vb/attachment.php?s=&postid=1814273">
Depending upon your use, you can get anything you want... performance, bells and whistles, economy. I don't game, so I'd be interested 2 or 3 PCIEx16 slots, + 3 or 4 PCI slots. I also like PS/2 and Parallel ports so as not to crowd the UBSs so much. Onboard sound, but no onboard video.
Got this spare power supply. It is a basiq [sic] 500W unit, but should do for now. I only have one graphics card, one harddrive, and I am not OCing the rig yet. <img src="http://www.elitetrader.com/vb/attachment.php?s=&postid=1816622">