Front Side-Bus question.

[fst1006]

Hi, ok pretty new to OC'ing.

i have here is:

1 x Intel P4 @ 2.53 GHz w/ 533 FSB
1 x Springdale Based motherboard. (dual-ddr)
2x OCZ PC3200 RAM


now, here comes the question!

I was recently reading an article on anadtech and they had a p4 2.8 doing a FSB at 333?!?!?!?!?

how is that possible? the effective FSB of the p4 2.8 is 533 / 4 for a total of 133. so in DDR terms thats 266mhz.

in order to get the P4 up to a effective DDR clock of 333 you need to boost up the FSB to 166mhz.

now in short, How do i get my P4 2.53Ghz up to a 166 FSB ( AKA DDR clock of 333)

so i just go into the BIOS of my MOBO, increase the FSB to 166?

now doesnt that also increase the MHz speed of the processor? ( <Internal clock> x <FSB> = <actual operating speed>)?

Thanks
Rob

[GokuSS2]

The board supports up to a 333FSB QDR. Getting there is another matter.
http://www.anandtech.com/mb/showdoc.html?i=1824&p=5

While the ABIT IC7-G was able to reach 270MHz FSB (1080MHz QDR FSB), the Albatron PX865PE Pro II was able to best that FSB overclock by 8MHz for a final overclock of 278MHz FSB (1112MHz FSB). As we've mentioned in other reviews, there have been reports of FSB overclocks as high as 1200MHz FSB from some motherboard manufacturer's own testing, but again, don't expect to see these kinds of overclocks with conventional cooling or retail processors anytime in the near future. It seems Albatron continues their tradition of great Pentium 4 overclocking motherboards with the PX865PE Pro II. We can see Albatron becoming a trusted name among enthusiasts just as ABIT's name gradually has.

[confus-ed]

Originally posted by fst1006
....I was recently reading an article on anadtech and they had a p4 2.8 doing a FSB at 333?!?!?!?!?

how is that possible? the effective FSB of the p4 2.8 is 533 / 4 for a total of 133. so in DDR terms thats 266mhz.

in order to get the P4 up to a effective DDR clock of 333 you need to boost up the FSB to 166mhz.

now in short, How do i get my P4 2.53Ghz up to a 166 FSB ( AKA DDR clock of 333)

so i just go into the BIOS of my MOBO, increase the FSB to 166?

now doesnt that also increase the MHz speed of the processor? ( <Internal clock> x <FSB> = <actual operating speed>)?

For peace of mind if nothing else your reasoning is correct ! (you need a board bios that lets you change the fsb though)

The last bit doesn't make too much sense though ... isn't increasing the cpu 'speed' what we are actually after ?

I think you'll be lucky if you can increase the FSB much past 150 ....

Then there's all that stuff about 'sychronous' & 'asychronous' memory clocks ... some boards have the memory bus to fsb ratios fixed some don't ... so you just can't overclock on some boards merely by increasing the fsb because the fsb is tied to a ratio of memory speed...

Simple answer open bios see if you can push up the fsb !! (try small increments & work up checking stability ... 'boot' is not stable necessarily !!!)

Oh watch those temps !

[ilovetheusers]

Originally posted by fst1006
Hi, ok pretty new to OC'ing.

i have here is:

1 x Intel P4 @ 2.53 GHz w/ 533 FSB
1 x Springdale Based motherboard. (dual-ddr)
2x OCZ PC3200 RAM


now, here comes the question!

I was recently reading an article on anadtech and they had a p4 2.8 doing a FSB at 333?!?!?!?!?

how is that possible? the effective FSB of the p4 2.8 is 533 / 4 for a total of 133. so in DDR terms thats 266mhz.

in order to get the P4 up to a effective DDR clock of 333 you need to boost up the FSB to 166mhz.

now in short, How do i get my P4 2.53Ghz up to a 166 FSB ( AKA DDR clock of 333)

so i just go into the BIOS of my MOBO, increase the FSB to 166?

now doesnt that also increase the MHz speed of the processor? ( <Internal clock> x <FSB> = <actual operating speed>)?

Thanks
Rob

Can't stand how complex this stuff got. used to be so easy, bus speed is set and CPU speed is a multiple of bus speed. Well, it still is but we also threw the FSB and the DDR in the mix to confuse things. That coupled with how everyone seems to use different terminology to refer ro every single component, it's really hoses things.

You have:
FSB Clock: Normally seen at 100, 133, 166
FSB/DDR ratio: the ratio between the FSB Clock and the DDR
CPU multiplier: Locked on the P4 - no way around.
Quad FSB Pipelines on a P4 mulitplies FSB Clock x4
DDR RAM multiplies he FSB Clock modified by ratio x2

Example:
Bob owns
2100 (266) ddr
P4 2.53ghz/533mhz

He sets the FSB Clock to 133mhz
The FSB/DDR ratio to 1:1
The multiplier is locked at x19
DDR is 266, FSB is 533 and the CPU is 2.53 and the computer is happy.

To overclock he ups the FSB Clock to 145. The DDR is 290, FSB is now 580 and the CPU is now 2.75ghz. He also ups the voltage a tiny bit too so it can run properly.

Example 2:
Jill owns
2100 (266) DDR
2.0ghz/400mhz

She sets the FSB Clock to 100mhz
The FSB/DDR ratio to 3:4
The multiplier is locked at x20
DDR is 266mhz, FSB is 400mhz and the CPU is 2.0ghz and the computer is happy.




To answer you question directly I don't know what they had clocked at 333mhz as if it was the FSB Clock the thing would run at 6ghz and wouldn't boot unless you had it in liquid air or something. But, they most likely played with FSB Clock and the FSB/DDR ratio to get the speeds to where they want.

Like confused said, watch the temps! You burn up your system and nobody is going to be to blame but the guy who made the setting change. Also, it's good to have really decent ram like corsair-xms that is made to overclock. Personally I just don't do it. The 10-20% increase just doesn't seem worth the extra $$ for the ram and the potential instability and high temperatures.