>I have a choice to buy one of these two rather new Dell computers from a reliable source. Please help me weigh out the best option (both are XP SP2 and do not come with monitor)
>
>You'll see that I am basically trying to decide between a Dual Core 3.0Ghz on a 10,000 RPM drive with a second 250GB 7,200 drive for about $400 more than the QUAD core 2.66 Ghz on one single 250GB 7,200 RPM drive. Which configuration is a better (overall faster) developer and and basic power-user stuff (i.e. VFP, Office, Visual Studio 2008? I do not care about the $400, I just want the overall best machine. For some reason the DUAL Core 3.0 Ghz on 10,000 RPM Hard Drive and a separate 250GB 7,00 RPM drive seems better than QUAD Core 2.66 Ghz on one 7,200 RPM Drive. What about the video cards?
>
>System 1:
>-------------------
>Dell XPS 690
>DUAL core Intel Xeon Processor 5160 3.00GHz, 4MB L2,1333
>4 GB Ram
>Primary HD: 80 GB SATA Hard Drive DataBurst 10,000 RPM Sata Western Digital Raptor
>Second HD: 250 GB Sata II 7,200 RPM
>nVidia GeForce 8800 GTS video card
>Price : $2,000
>
>System 2:
>----------------------
>Dell XPS 690
>QUAD core Intel Xeon X5350 2.66GHz 8MB CACHE 1066MHz FSB
>4GB Ram
>250 GB EIDE SATA II Hard Drive 7,200 RPM
>Nvidia GeForce 8400GS PCI EXPRESS VIDEO CARD
>Price: $1,600

80GB WD Raptor 10K ~$170

nVidia 8800GTS 320/640MB ~$300/$400
nVidia 8400GS ~$60

Xeon 5160 ~$950
Xeon 5350 can't get a current price on this CPU but it was significantly more expensive than the 5160, at a guess $500+

So, system 1 has an extra $170 HD and a video card that is either $240 or $340 better, depending on how much video RAM it has.

Both systems have early Core 2 - based Xeon CPUs (socket 771). Xeons are server chips, optimized for heavy continuous use (high utilization) and throughput, usually with relatively large caches. These machines may also use expensive ECC RAM, which is recommended for servers.

Single-threaded apps will be slightly faster on #1 since its clock speed is slightly higher. Multi-threaded apps will be faster on #2. Either CPU is plenty fast enough for the apps you list.

Either video card is plenty fast enough for anything except gaming, where the GTS has a big advantage.

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The big question is, really, what are you planning to do? If this is a developer workstation I'm not sure either machine is a good deal. Yes, you're probably getting some server-grade components but you can probably get equivalent or faster hardware brand-new for the same or lower prices if you switch to socket 775 Core 2 CPUs and chipsets. These are current mainstream fare, inexpensive and widely available.

In contrast, if you go with either of the Dells you've spec'd, you're stuck with a Socket 771 mainboard, and maybe with ECC RAM. If either of these fail you're looking at hard to find/expensive replacement parts.

For workstation use, Xeons are not significantly faster (if at all) than standard Socket 775 Core 2 parts at the same clock frequency and with the same cache RAM.

The way it looks to me, the prices you've been offered are probably a large discount over what those machines cost when they were new. They may still be higher than new Socket 775-based systems that are faster and more mainstream.