Underclocking = artifacts?!

Okay, I decided to make a 2D and 3D profile in ATiTool, with the 2D profile clocked at (300,300) (oh yeah, I have a 9800Pro flashed to XT) and a 3D at (415,370). Anyway, I started playing a game at the 3D profile settings and it ran perfectly fine (as it always has). Out of curiosity, I ran the game on the 2D profile and I got both a TON of snow and big triangles dancing all around (mem artifacts). Then I ran ATiTool's max clock finder starting from both settings, 3D went up just a tad (I already knew the max clocks w/o artifacts) while the 2D artifacted horribly and got worse as it automatically lowered the clocks.

In addition, in just general use at 300,300 (i.e., 2D use) text gets garbled and everything in general gets messed up (except ObjectDock, oddly).

Anybody have an explanation for this?

Maxtor disgraces the six letters that make Matrox.