Computer Upgrade Suggestions

In the next few weeks I should be getting a new computer at work and I wanted to get the opinions of TG readers.

Here are the current specs on the computer I'm using:
Brand: Dell Optiplex 270GX
CPU: Intel Prescott 2.8Ghz
Ram: KingstonVR: 1Ghz
OS: XP Pro
PS/MB/HD/CD/Vid Card/Sound all Dell preinstalled

I do a considerable amount of work with Excel (exceeding 20,000 rows) and large amounts of data from our database and find that the system often chugs through formula computations and analysis.

I'm considering suggesting the following:

Brand:Self build
CPU: Intel E6600 (2.4Ghz)
Ram: Corsair 2Ghz (800Mhz)
MB: Asus

One question is have is would there be a difference in computational power between these two CPU's? My current one runs at 2.8Ghz and the E6600 runs at 2.4Ghz, would that not be slower? How much of a factor is the FSB of the Motherboard? I'm not that familiar with the impact of FSB so any input would be greatly appreciated.

Thanks for anyones input!

There will be a huge difference between the two, but the increase to 2GB of RAM will make a huge difference in and of itself. GL

Not only the 2.4GHz the 1.8GHz Core2 or a 2.0GHz Athlon64 CPU kills a 2.8GHz P4. That is because these CPUs simply do much more work on each clock cycle; While the main intent in building the Pentium4 was it's ability to work at always higher clock rates, it's efficiency was very low and even dropped with the (then new) Prescott architecture.
Aside from inefficiency, the P4s are also much hotter and consume more power that Athlon64s and Cpre2 CPUs. (The newest athlon64 single cores, while having a slight performance edge over Pentium4s, consume only 45W against the 89+W of a P4)

Theoretically yes, but the FSB never gets satureded to that point and either 800 or 1066 are enough. The fact is that newer CPUs are just more efficient and for the moment, Core2 CPUs are just the best, being matched only on the midle and lower end by AMDs X2s.