Graphics Oddity?

Ok so I finally got around to reformatting and putting in xp prof. I also was playing around with my settings for my video card and found a strange oddity. I know this sound super wrong but I swear it is happening.

I used to use the High performance setting under the graphic card's tab (ie turning off anti alias, lower detail, and so forth) because I thought I'd get a decent speed boost. A few games I was running were getting about 60 fps and zooming out ie more stuff dropped it to under 20 fps. It worked for me but you could see flickering in the game, jagged edges, pretty much bad detail.

Well I decided how much of a hit /slow down could it be if I changed all those settings in the tab to High Quality. Anti Alaising 6x on, high detail. 16x antiscopitic filtering... But what do I get. The game still stays at 60 fps and zooming out only drops to 30 fps constantly. This is actually an increase in fps , details, no flickering and so forth.

I know from my previous experiences all this stuff turned on should have totally like brought the game to a crawl and dropped the fps. However I am experiencing the reverse of this for some reason.

Is anyone else experiencing similar things?

Hopefully in the near future I'll pick up a copy of doom3 and benchmark. Until then I'll stay in the high quality mode till I meet something that is slowed down to the point I have to think otherwise.

Dell I6000d
1.86 ghz
1 gig 400mhz ram
80 gig HD
Intel Pro 2915 a/b/g Wireless
15.4 " WXGA
Ati X300 128 mb
Nec Dvd +- RW 6500A