KX7
Welcome to the Overclocked forums!
The ratios are different settings which allow you to put the AGP and PCI busses back into spec at higher FSB speeds. Ordinarily... 100MHz FSB/33 Mhz PCI/66Mhz AGP or 133FSB/33PCI/66AGP. When you overclock the FSB, the other two also go up. The reason the PCI and AGP stay the same at 100 and at 133 is that the determining ratio (called divisor or divider by most of us) changes.
At 100, its 1/3 of FSB = PCI. AGP is always 2x PCI
At 133, its 1/4 of FSB = PCI.
At 166, its 1/5 of FSB = PCI.
Here's your system- 11.5x140= 1610 Mhz. PCI= 35 Mhz AGP= 70 Mhz.
The abit board you and I have allows us to kick on the 1/5 divisor anytime we want as opposed to it coming on automatically around 166 FSB like on other kt333 chipset boards. The reason to do so is to keep the PCI and AGP in spec or close to spec. PCI devices and AGP video cards often have problems when the PCI and AGP busses get too high above their specified speeds... typically around 40 for PCI and upper 80's for video cards. By dropping the PCI and AGP back down, we can continue to overclock our ram and CPU without worrying that these devices will cause problems.
Turning the 1/5 divisor on while still below 166 FSB will actually underclock the PCI and AGP busses. It is not likely that an 1800+ will be able to get to 166 FSB unless the chip has been unlocked and is running on a smaller multiplyer. Since you have a really nice 333 board, it would be a good idea to unlock your XP, especially if you have DDR that is rated to reach high speeds... PC2700 and up. You could then set your cpu to a 10 multiplyer and try to hit 166 FSB with the 1/5 divisor turned on. Or if your memory is not up to the challenge, you could leave your FSB where its at and try for 12x140, for an extra 70 Mhz on the CPU!
Voltage: All voltage hurts the cpu and causes electron migration which will eventually kill it. But we're talking years and years. Heat is a more dangerous enemy in the short term, and heat is also caused by voltage. If your cooling is adequate, raising the voltage will not significantly decrease the lifespan of the cpu... at least not to the point where you wouldn't have upgraded a couple of times already. A lot of us feel that 1.85v or even 1.9v is ok if the CPU temp is below 45C with air cooling when the CPU is at full load. Watercooling raises the bar some because it is more efficient.
I understand the ratios now. After i let Prime95 run for a while... maybe ill push the FSB some more. RAM should be up for the challange. I've got a stick of Samsung 512MB PC2700...
