overclocking fsb limit reached?

hi

I tried to overclock in bios by raising the FSB but could only raise by 15 mhz till hit the line. now i have to say i have some booting problems (sometimes the monitor wont turn on) but i cant understand why i cant overclock anymore than that?

so does anyone know what could cause this? the mobo is supposed to support overclocking but i wonder why i cant get past 15mhz FSB increase?


here's my system:

GPU: SAPPHIRE HD 4850 PCI-E 512MB GDDR-3 HDMI
Mobo: ALiveXFire-eSATA2 R3.0
PSU: COMPUCASE PSU 550W 12CM ATX12V2.0
CPU: amd sempron 3400+



thanks


PS. when i boot after oc the system just hangs on POST.

 

what cpu are you using? the maximum system bus yourboard handles is 1000mhz, also when increasing your system bus you will also have to increase you vcore as the cpu doesn't have the required power for the extra bandwidth increase, that can also be a result of a non post or stablity issues within the OS.

so what you want to do is check what cpu you have, check the cpu's stock system bus frequency and also check the max voltage the cpu can handle (google)
post back with the info requested and we will help you from there

btw: also check your motherboard for system bus jumpers on the motherboard sometimes you've got to adjust the jumpers to what frequency your going to be using but you might as well set it to the maximum your board supports after all it's just a bus cap (limit).

 

Amd sempron 3400+


from bios i was able to raise vcore to maxium of 1.4 (from 1.35)
but this didnt help


the bios also has some "untied clocking" feature but i dont understand the idea behind it, it allows me to set pci-express to 100, 101,102 or 104 mhz (i know pcie is for graphics)

 

i think the problem is that my memory runs at 266 mhz and when i raise the FSB it goes over it. am i right?

soo.. should i change it to run at 200mhz so it wont go over 266 so soon?
or is there better aproach to this?

any advice? thx!

 

Try the motherboard manual. They usually come with the overclocking details. check it out on the mobo website. May be its the max limit for ur MB..

 

Hi sorry for the late reply been busy. I just had a look at the spec's of your cpu and it system bus is 800mhz. apparently you can get the cpu to 2.25ghz using a bus frequency of 225mhz x4 = 900mhz system bus. leave you vcore at 1.4v. memory bus try clock it to 225mhz as well. The untied overclocking allows you to overclock the pci-express x16 bus frequency 100mhz is always stock, I've never messed with it but it increases the bus cap (limit).