locked P4 multipliers? I don't get it...

[h4x0r]

I've been reading some articles about OCing and noticing that some of them mention how the multiplier on their p4 chip was locked...since it wouldn't be possible to change the processor multiplier, how do you know before you buy the processor, what the multiplier is?

 

[ChampionAtTufshop]

first you need to know whether it runs on a 400mhz fsb, 533, or the new 800mhz fsb
the cpu freq, respectively, is 100, 133, and 200 mhz

what you do is take the advertised speed (like say a new p4 3.0C processor which has 800mhz fsb) and divide it by the cpu freq to get multiplier

in the above case, 3000mhz / 200 mhz cpu freq = 15
therefore the muliplier is 15

so cpu speed / cpu freq = multiplier

 

[KillaBong]

Divide the full clock speed by the bus speed. Such as 533 / 4 = 133fsb , 2533mhz / 133fsb = 19
So the multiplier on 2.53ghz p4s is 19.

Edit: looks like you beat me to it

 

[h4x0r]

I see, so that is why the p4 1.8ghz processors are so good for overclocking, because of the low multiplier?

 

[Dragonfire1357]

Actually you would want the cpu with the highest multiplier cause then you get more speed increase out of each fsb increase

 

[ChampionAtTufshop]

Originally posted by: Dragonfire1357
Actually you would want the cpu with the highest multiplier cause then you get more speed increase out of each fsb increase

but a higher fsb is better than higher overall mhz
thats why amd ppl lower the mult and jack up the fsb

the 1.6a and 1.8a were both pretty damn good ocers depending on stepping/week and whatnot
every once in a wihle manufacturers put out "miracle" chips ...it just happens

like the current C variety p4's are expected to be really good ocers with insanely high fsb's

 

[h4x0r]

yeah, the 2.4C looks like it will really deliver well. Back to the 1.8A though...what would be the limmiting factors of this chip when dropped in a board like the abit bh7 with some good ram? I don't have a lot of money to blow and this looked like a good way to go for OCing and stability

 

[SupermanCK]

limiting factors:

dud cpu
dud ram
dud mobo
dud psu
dud heatsink

but looking back at the past 1.8a....especially the newest stepping C1s... you would most likely be getting close to around 3.0GHz o/c range.

 

[Confused]

The multipliers on all Intel chips for quite a few years have been locked because there was problems with resellers taking lower speed (and therefore cheaper) chips, changing the multiplier, and remarking them, then selling them on as a higher speed, and for more money.

AMD's multipliers are locked (well, other than the very newest Tbreds and Bartons), but they have left a way for the multipliers to be unlocked, if so required


Confused