Hello all, i m new here

[v0203]

Hello all, i m new here and new to oc too.

Here are My system:

AMD XP 2400+ (2GHz) TbB
ASUS A7v8x VIA KT400
Samsung 512MB PC2700
Leadtek gf4 Ti4800SE
Maxtor HDD 40GB
PSU 350w

I have a fan(Coolermaster HAC-V81 XDream Heatsink & Fan SKT A Upto Xp2800 Speed Adjustment), but everything else is stock.
The CPU orginally runs at 2000MHz with a system clock 133 & Multiplier 15.

Now i overclocked it upto 2128 (152x14) without touching the voltage(not planned to incase it fried anything). I tested it with prime95 for more than 12 hours, no error reported.

But when i restart my computer, it crashes. So i press the restart again and it automatically loads into BIOS, and it say that the BIOS is running in safe mode and the frequency is inconsistent with the manufacture. Once i switch off my comp and turn it back on, it runs fine again. So is there anything wrong?

And also what is the best clockspeed and multiplier i can get with a normal voltage and the spec of my machine?? please advice,

Thank you.

[Steven4563]

are your pci slots running at 38mhz ?? if so there could be a problem something dont like it try running at 166*13 = 2.15ghz


WELCOME TO THE FORUM !!!

[v0203]

how to check what PCI BUS speed is?

I have wcpuid, but doesnt seem to tell u the PCI speed.

or m i just being a n00b.....

pls tell me how to find out. thanks

[c627627]

Oh yeah, watch out there v0203, you have a non PCI locked mobo.

152/4=38 is just on the edge of safe.

There is something called a PCI lock and nForce2s have it and VIA mobos do not.

Increasing the FSB changes the speed of the whole motherboard and everything connected to it unless the mobo has a PCI lock. PCI lock is good because it saves your other components from the negative effects of overclocking.

VIA mobos use a divider.

First of all FSB is more important than MHz.
MHz is FSB x multiplier but the idea is to have the highest FSB possible. Without a PCI lock, that may not be an option. This is why:
Lets’ say VIA mobo has a /4 divider for 133 FSB and up, then a /5 divider kicks in for 166 FSB and up.

That also means with overclocking to say, 180 FSB: 180 /5 = 36
...and then overclocking even more: 190 /5=38.

38. That’s 15% out of specs your hard drive and sound cards and everything connected to the mobo is running out of specs.

You go further than that and you’ll be entering into hard drive scrambling territory... unless you have a PCI lock which nForce2 does and VIA does not.

[Bogie]

I have a little prog called overclocking calculator, you put in the fsb and it shows. I can e-mail if you want it.

[c627627]

133/4 is the same thing as 166/5 that's equal to 33.3333 specs.

If your mobo has a /5 divider than all it does is switch to /5 after 166 FSB.

[v0203]

My mobo saids : Max Bus Speed = 333MHz

So its 333 = 166FSB x2 right:confused:

So i have a /5 divider ???

Is that how it works out?

But my CPU is XP2400+ 266MHZ FSB 256Cache

So is it 133 or 333 MHz ?????????????????????????

[Caviman2201]

I have the same type of MoBo... a KT400... what c627627 was trying to say is that VIA chipsets have a divider feature while nForce 2 chipsets have a PCI lock feature. When you overclock the FSB in a nForce Mobo, it locks the PCI bus speed at 33MHz... regardless of where your FSB goes, making nForce MoBo's much better for overclocking.

VIA chipsets, on the other hand, run what's called a divider. What this does is detect what the stock FSB of your processor is and set the divider accordingly. When you run a processor such as your (and my) 2400+ with it's 133MHz (DDR266) FSB, the chipset sets the divider to 1/4. This allows the FSB to run at 133MHz and divides that speed by 4 to get the PCI's 33MHz. When you install a 'Barton' core processor such as a 2500+ and up, the KT400 will detect it's stock speed as a 166 (DDR333) FSB and up the divider to 1/5 accordingly. This allows the FSB to run at 166 but divide that number by 5 to allow the PCI bus to continue to run at 33MHz.

To answer your question, you have both a 1/3, 1/4, and 1/5 divider for your KT400's supported 100, 133 and 166MHz FSB's. It just sets those dividers according to the stock specs of the processor you install.

MY question is, is there any way at all to change the divider without changing the processor, as this would allow running a 160MHz FSB (temperature dependant) without frying the PCI bus?

[c627627]

That's a good write up Caviman2201.

Dividers kick in automatically.

133 FSB will have a /4 and
160 FSB will always have a /4 for your mobos.
160/4=40 (a bit too far out of specs for most people)

166 is when the /5 kicks in although it may actually do so at 164 or 165 for some mobos.

I wouldn't test it though as 165/4 may seriously damage your system.

[v0203]

Thankyou very much for both c627627 and Caviman2201. I understand alot more now.

So in my case i m running 152 x 14 which mean 152/4 = 38mHz for the PCI which is quite dangerous :eek: thats y u said its near the edge.

so, does it mean that if i try 166x13 its even more safer? (166/5 = 33.2mHz), can my RAM (PC2700) takes that?

(bear in mind that i would not like to try put up the voltage.....)

[Maxvla]

sure. pc2700 is actually spec'd to run 166mhz :)

[stratcatprowlin]

[QUOTE]Originally posted by v0203
[B]Thankyou very much for both c627627 and Caviman2201. I understand alot more now.

So in my case i m running 152 x 14 which mean 152/4 = 38mHz for the PCI which is quite dangerous :eek: thats y u said its near the edge.

so, does it mean that if i try 166x13 its even more safer? (166/5 = 33.2mHz), can my RAM (PC2700) takes that?

yes do that and ull be totally safe.The pc2700 runs at that speed at default anyway.Hopefully ur multiplier is not locked?

[stratcatprowlin]

sorry, ur post wasnt there when i was posting. I wouldnt have posted that if i saw what u wrote

[Maxvla]

Originally posted by stratcatprowlin
sorry, ur post wasnt there when i was posting. I wouldnt have posted that if i saw what u wrote
better twice the answers than none at all :)

[v0203]

yup, thank you very much for the answers:)

I m now running @ 166x13 (2158 MHZ).

in my Bios settings, the clock frequency listed (149/37, 150/30), so does that mean even when i use 150 FSB, it uses the 1/5 divider?

[Maxvla]

appears so. you are lucky it changes so early. most boards wait until you are right on the number for the changeover.