Question about FSB clock etc...

[kantona]

Hi all.
I don't know much about OCing etc, and I'm new to all this freq and timings calculation.
I am wondering, how does changing the FSB clock reflect on the system.
I have Athlon x2 4850e and MA78G-DS3H rev1.0. I know the clock change has effect on the HT Link Freq and the memory operating freq but looking from the CPU perspective you can reach the same CPU operating freq with different combination of CPU ratio and FSB (CPU) clock.
For example, if you want to overclock to 3GHz you can:
12.5x 240MHz = 3000
10x 300MHz = 3000
9x 333MHz = 3000
etc
However, with the standard FSB of 200MHz, how does raising it to 240, 300 or even 333 affect it? I think my mobo allows me to go as high as 500MHz, isn't that a huge difference compared to original 200MHz?
I am asking this because with my AMD cpu I can only control the memory freq trough CPU/# divider and it will help me to know if raising the FSB too much is gonna get me into trouble.

On another note, my cpu is not compatible with DDR2 1066 but if I buy 1066 modules and using freq manipulation, would the memory actually work at 1066? It wouldn't even be OCing the memory because a 1066 module is designed to work at 1066.

I would appreciate if someone can clear these qiestion for me. Thanks.

[kantona]

Re: Question about FSB clock etc...

Lsdmeasap, or someone, can you explain a bit more about this question please.
My problem is that due to AMD cpu design (didn't know when selecting cpu) my mem freq is directly a result of the cpu freq using a CPU/integer divider.
I am new to OCing and I would like to figure out my options to control my mem working freq.
Thanks in advance.

[Lsdmeasap]

Re: Question about FSB clock etc...

I do not know how AMD Works myself, but I believe it is like Intel's new i7/X58 setups.

What you want to do is find the higher stable FSB you can use within your respective voltage and temp desires then adjust your memory mutli to whatever would be closer to your rams spec speed. Higher FSB is better, but you may need to find some middle ground so you can run your ram at a respectable speed depending on your memory multipliers.

If your CPU is not compatible with 1066 ram, then no you cannot use it. I have seen this cause many issues, normally the boards will just not start at all. What you can do though is buy some quality 800Mhz ram and overclock it to 1066+ if you like

[kantona]

Re: Question about FSB clock etc...

Thanks Lsdmeasap.
This memory divider thing seems to be present only with the Athlon x2. The Phenom range allows you a multiplier in BIOS so it doesn't depend on cpu ratio.
But for my processor the memory divider depends directly on the cpu ratio, lower cpu ratio equals lower integer in the divider (higher freq for the ram).
But if you lower the cpu ratio you have to raise FSB unless you want to lose out on cpu freq.
My board seems to work fine with FSB raised to 250MHz from the original 200MHz. All voltages on Auto. I understand you can not know all boards out there but out of experience would you say I can raise the FSB to 266MHz without raising northbridge voltage? I won't go too high with the cpu freq so I guess no need to bump up the cpu voltage. I can control the cpu freq with the ratio, no problem. Higher FSB, lower cpu multi so I will still keep the cpu at similar freq. Biggest dilemma is going to 266MHz FSB and how will that affect the board as a component.