From Anandtech's site:
http://www.anandtech.com/showdoc.html?i=1270&p=1 This tweak didn't help me get my AGP video card stable at 133 mhz, but it might help some of you. Bottom line is, DISABLE "SIDE BAND ADDRESSING" or SSB, which seems to prevent running at 133 mhz or 148mhz. This is a potentially simple fix for some cards.
If you don't have this setting displayed in bios, you can access it by using "Powerstrip".
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