Overclocking the 1.8a on Abit TH7-II

Hello, I tried to overclock my 1.8a SL63X on my TH7-II raid but no luck yet. I would like to get it to run at 2.4 In the soft menu I tried different settings, user define and changed the external clock from 100/33.33 to 133/ and bumped up the voltage to 1.65 but then I get no video and have to clear cmos. Do I have to change any of the default dip switchs on the mobo? If anyone could help a overclocker brother out and maybe tell me their working settings in the soft menu, maybe I could try it and see if it works. My mobo and chip is factory, I have not done any wiring mods to it, not sure if I have to.

Thanks

First the pci agp bus is going toooo fast you must fix it at 33 .
What bios do you have? 38, 7c. bf, bw.
After you fix thine pci agp then take the fsb up slowly maybe to 115 then see how things are going. you should be able to get to 120 or so. don't know how your ram will do. bump up the vcore just alittle 1.55. the ram should go but maybe not ...all systems are different. you can set it to 300 and see how high you can raise the fsb. up the vcore if things get unstable..

start out with stock voltage and the memory set to 100mhz and a 3x mem multiplier. set all of the agp. pci stuff to fix. ( th7ll'S are notorious for under volting, you might actully have to set the voltage to 1.6 or higher to get a correct 1.5v reading to start out with) then boot it up. it should start up to its rated frequency (1.8) then go into bios and add 10 mhz to the fsb and reboot. with each 10 fsb increase the processor speed will increase 180mhz (18x10). keep adding 10 mhz till the cpu fails. (ie 130 fsb) once the cpu fails, shut down computer, unplug all power for at least 30 sec. then restart. the mb should boot up to default values( 100mhz fsb x 18 and memory at 4x) reset the mem multiplier to 3x and up the voltage to the cpu .10v to 1.6v. then put in the the fsb speed that the cpu failed at (ie 130fsb)when you were using 1.5v. volts. the increase in voltage may be enough to allow it it to run at this higher speed. when the cpu fails again, do the afore mentioned procedure and bump up the voltage and try again. most people agree 1.75 volts is the max u want to use. this is the procedure i used to find the maximm oc'd speed of my 1.6a. ultimately i was able to achieve a 2720 cpu speed. however if you are using stock pc800 and stock drcg's they may fail b4 the cpu does. that is why it is important to keep the mem multiplier at at 3x. ultimately you may have to go with pc1066 and or 533 drcgs to get the maximum speed of your cpu.

"better said" Flapperhead

thanks
Logger

What I tried today

Here's where Im at today. I have the BW bios. The settings that I got to run as follows.
125/33
x18
fix 66.00

1.70v actual 1.60 in hardware doctor

300
4x there is no optin for 3x

anything over the 125 the system either doesn't boot or it tries to boot and goes through the post and reboots before it starts xp. So I guess maybe that's it. It seems like 2250 might be it?

Thanks

No 300 in the bios that doesn't sound to good. Go back to 7c if you wish and set it to 300 and you should be able to go higher.
I can't believe there is no 300. should be 300, 400, auto I would think. BW bios I heard the fix doesn't work anyway..

I have choice of 400, 300, Auto 4x 5x 6x 7x under the RDRAM bus freq. menu I now have it set at 300 4x
On boot up it says 375/125 for the mem

If I change it to 400 4x it doesn't boot into windows

the top is as follows
CPU operating speed; User define
External clock 125mhz/33 mhz
multiplier factor x18
AGP; fix 66mhz

CPU power is 1.7; there is not option to put it to 1.75

Set the diff current to 6 or 7 Abit says its more stable there.
125fsb is what some chips will do and no more. Thats about what my 1.8a would do.

from what you"ve posted it looks like youre running the memory at 300. so the failure is most likely because the cpu has reached its maximum. you might want to try to up the voltage to 1.7 or 1.75, it may help get a higher speed. if that doesnt work then youve reach the maximum overclocked potential of your cpu.

125 FSB was the max stable fsb my 1.8a would do too. (128 worked for about 10 minutes. I never was able to post @ the magic 133 but my Samsung 45ns PC800 RAMBUS was able to do 400x125 giving me 500mhz FSB, great performance doing so.