I have a generic ( Pine Tech ) M/B and it supports 100Mhz fsb for up to PIII's but in the cmos it doesn't have the option of setting agp speed to 2/3 or 1/1. Does this mean if i try to o/c my cely 300 to 450 it will kill my agp card ?? if so how would a cpu which is designed to run 100Mhz fsb work on my board without this agp speed setting??
Mobos generally auto detect whether you have a Celeron or a PII/PIII by reading the state of pin B21. So if you plug in a PII or PII it will automatically set the AGP divider at 2/3. There might be a jumper to select the divider to override pin B21 - it might be labeled as a 66/100 jumper. You need this to force the AGP divider to 2/3 for a Celeron since the mobo would normally set it at 1/1. If you don't have this capability you can tape pin B21 and fool the motherboard into thinking your Celeron is a PII or PIII. Here's a link to the procedure over at Tom's Hardware: www6.tomshardware.com/cpu/98q2/980514/ .
i'm a little confused? i think i've seen the jumper setting you're talking about, but i can also change the fsb within cmos settings. so if i set the fsb to 100Mhz and leave the jumper on 66 it should be alright ?
This jumper doesn't change the FSB, it changes the AGP divider ratio. The 66 position will set the AGP divider at 1/1, so if you O/C your Celeron to 100 MHz the AGP clock will be 100 MHz. To O/C your Celeron to 100 MHz, you need to set the jumper to the 100 position to set the AGP divider to 2/3 and the AGP clock will be at 66 MHz. This is referred to as a b21 override capability. This is the way it works on my old Soyo SY-6BB motherboard.
Hey, I was thinking about that yesterday when figuring about something to do about my cely333@puny375 system. Maybe my G200 doesn’t like 80+MHz so I was looking for a jumper like that on my Asus P2B but couldn't find one.
Does that mean I must do the b21 override thing?
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