I can confirm that this isn't just an issue with VIA chipsets.

In the end, I decided to set up my dual-boot W98+DOS/WXP system on an i865 LGA775 platform with a C2D processor.

I installed the system the usual way: OS, chipset and component drivers, DirectX, and software. However, the 3DM01 test results surprised me with their low scores—I’d only had a P4 630 Prescott (3 GHz) in the socket so far, but I still expected at least comparable scores to my previous system with an nForce3 250 and a 2 GHz Turion ML. But the Pentium fell short by over 2,000 points, even though it runs at a higher clock speed and has a dual-channel memory controller.

It immediately occurred to me that the problem might be with AGP texturing, even though it was enabled in dxdiag. I set the AGP memory in the BIOS to 0 MB, but the 3DM01 score didn’t change—it remained around 6,700 points.
The problem was solved by reinstalling the chipset driver—after that, 3DM01 reported the AGP memory size according to the BIOS settings, and the score almost matched that of the Turion. The driver (FW 45.23) and graphics card were identical on both systems (Quadro FX500, also known as FX5500)

So this is the second instance where installing the chipset driver after the graphics card driver helped.