400vs533Mhz FSB? TEACH ME!

Hey guys. I need some help here: right now I'm running an ASUS P4S333 (SiS 645) board with a P4 1.9Ghz Williamette CPU. I just started trying to overclock...i can get up to 2.169Ghz, but that's it...I can get farther if I bump up the Vcore a bit, but then my LAN card doesn't work right, and soon after other PCI cards don't work right...
1) This means that I need to try to find a dividing ratio to try to lower the speed of my PCI/AGP devices, right?
2) My P4 retail box says it runs at 400Mhz...what does this mean, and why do the Northwoods run at 533Mhz? What does that mean, functionally? Can I still use the same motherboard? I think my board says it will take the Northwood chips, but if it's designed to run at a different FSB speed...then wtf? Can someone teach me about this stuff? I think I've seen the terms "400Mhz/100Mhz" and "533Mhz/400Mhz"? What do these refer to and:
A) how does this affect the way I choose a mobo/CPU combo for building a new system and
B) how does this change the way I need to approach overclocking?

Also, the only thing i've been doing to overclock is to increase the frequency(?) setting that's default at "100/33". This is the CPU/PCI speeds, yes? What else should I be doing other than jumping up the Vcore when needed? Obviously I don't know squat about this...please help! I Know it takes a lot of time to type up a real explanation, but please help out a fellow enthusiast!
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  1. oh yeah:

    Intel P4 1.9Ghz Williamette w/retail sink
    Asus P4S333 (SiS 645 chipset)
    2x256MB DDR333, i forget the brand
    Leadtek Winfast Titanium GeForce 3 Ti200
    Soundblaster Live! OEM
    WD 800JB Second Edition 80GB HD
    IBM Deskstar 75GXP 40GB
    Memorex 40Maxx 40x burner
    Plextor 12/10/32A burner
    Altec Lansing 2.1 excellent solution speakers
    POS 17" Monitor (hey, it was free...)
    Generic NIC/Modem/keyboard
    My favorite mouse = "Microsoft for Gateway 2000" mouse passed down from 5 years ago...still the best, don't dig the opticals that I've tried.
    Lynksis Etherfast 4-port router
  2. 1. It probably does.. if that is possible with that mobo. I'm not a P4 OC'ing expert.
    2. 400Mhz is the Quad Data Rate (QDR) of 100Mhz which is your real FSB speed. The effective speed is called 400MHz because the CPU can transfer data 4 times in eahc clock cycle (Hz). Some Northwoods are made to run at 133Mhz FSB (533 QDR) as factory default for speed increase.

    100/33 stands for FSB/PCI... the FSB*multiplier (which is locked with Pentiums) is your actual CPU speed. If your PCI voltage increases while increasing the FSB you can try increasing the I/O Voltage or PCI Voltage a little and see if that allows your PCI cards to run at higher speeds.

    My dual-PSU PC is so powerfull that the neighbourhood dimms when I turn it on :eek:
  3. just fyi,"willy's" are very poor o/cers,as i had one once also. along with that they get hot quik, so if you o/c watch your temps!!!!! you're probably at that chip's maximum now though. trade in(if only!!!)for a northwood (512 cache), and your o/c ing will be much better.!! the 1.8a can be o/c ed up to 3.0ghz.,depending on your luck. check out "overclockers.com" and check their "database" for results!!!! you'll truly be amazed at the speeds attained by smaller chips like the 1.6a and the 1.8a.

    <font color=purple> We can't all be heros,someone has to stand on the sidewalk and clap!!
  4. thanks svol/toester
    I overclocked the RAM by using the 3:5 ratio for CPU/MEM...and whoa was the performance increase huge.
    But hey guys, I'm running at 2.167Ghz idle at 33C, so heat-wise i'm fine...but if i go any higher my NIC doesn't work since I'm at 114/38Mhz...so I tried to jump to 133 to force the divider to make the PCI bus back into step...but no luck, it won't POST...does this mean that the CPU is simply not capable of handling the 133*19 clock? Probably not since that would make a 1900 default to run at 2527...

    Hey guys, I put this thread in the wrong place, please reply here:


    There has been some very helpful responses from Crashman here, I'd love it if you guys could offer your insight there as well...Thanks everyone!
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