Way To Speed Up Array Formulas

I have been lurking around for past month learning lots from MrExcel's wonderful web site. One of the many things I learned was how to improve my spreadsheets with Array Formulas, but today I ran into a problem on a new spreadsheet I'm building for work.

Here's the problem: I have 39 coworkers. For each coworker, I have 14 Array Formulas using SUMPRODUCT command with up to 5 "conditions", similar to this example:

{=SUMPRODUCT((user=$A$5)*(task=AO$3)*(DateChecked>0)*((Error="Error Removed")+(Error="Error Converted to an FYI")))}

Each condition such as "user" and "task" is a static named range of 5000 cells. This spreadsheet will hold one week's worth of my coworkers' work. This past week they have processed about 2500 items. To be safe, I doubled this number to determine the static named range size.

For each worker I have 56 columns (one for each possible task which a coworker can process).

So for each coworker, there will be 14 * 56 = 784 Array Formulas.

Currently my spreadsheet only has a single coworker defined, so I only have 784 Array Formulas, but it takes 35 seconds at 100% CPU Utilization when I press F9 (Calculate all formulas). Right now, I am running this on my Home PC (a 400 MHz PII PC with 256 Megs of RAM, OS is Win2000 at SP4 maint level and Excel 2002), but it is equally slow at work (1.7 GHz Celeron with 256 MB of RAM running Win2K SP4 and Excel 2K).

I haven't tested yet, but even if I assume a linear progression, with 39 coworkers I am thinking it is possible the amount of time for Excel to recalculate all the formulas will be 39 times longer than it is currently. This will be close to 22 minutes. That is a long time to wait! It will be even worse if my testing shows the amount of time Excel takes to evaluate the array formulas is exponential instead of linear...

...784*39 = 30,576 formulas...