NV43 into NVS440 possible?

Hello. At work we've got 81 pc's with similar specs, and their age is starting to show. So I was wondering if it would be possible to turn their geforce 6600 cards (asus, dev id 0141, pcie) into workstation graphics cards. The nvs440 (dev id 014a) appears to be based on the geforce 6600. But I can't find any way to actually do it or verify that it'd work. And I'm not particularily keen on flashing a card to render it useless.

The pc's have the following specs:

3ghz p4 prescott (530, lga775)
1,5gb ddr1 pc3200
hitachi 80gb sata drive
cdrw/dvd sata drive
asus geforce 6600 pcie
in a hp dc7100 housing (based on i915g chipset)

I've tried running rivatuner but that'll halt windows with a parity error. Can't even remove the thing atm.
gpu-z generates the exact same halt error.

Because as it is right now, rendering anything in inventor takes ages. A simple task of putting textures on a house would take over an hour. And the graphics assisted job would likely take less than 20 minutes.

And we're something like a business collage, so budget is tight. Which means we can't just go out and buy new computers every year.