P4 = locked, so why jumper setting?

vbimport

#1

Hello all,

As far as I know, P4 CPU’s have always been locked to a certain multiplier. Overclocking is limited to FSB overclock.
But I just found a manual for one of my old RD-RAM motherboards and it has a Switch to select a multiplier for both 400 and 533Mhz busses. It goes from 16x to 24x (400Mhz FSB) and 16x - 23x (533Mhz FSB) :confused:

Are there unlocked P4 CPU’s? Or is it a useless feature? Of course it’s not a big deal to test it, but I just wanna hear some opinions first :slight_smile:


#2

Yes there are a couple unlocked Intel CPUs floating around, but you won’t find it at any retail shop.

The jumper you’re talking about involves switching cpu bus speed and has nothing to w/ unlocking multiplier. Switching from 400FSB to 533FSB to 800FSB doesn’t change the fact that an Intel CPU’s multiplier will always be constant relative to the CPU model.


#3

Because

Northwood A = 400Mhz FSB

Northwood B = 533Mhz FSB

Northwood C & Presscotts = 800Mhz FSB

It also has to do with what kind of ratio that you want to OC your FSB.


#4

I’m sorry I wasn’t clear enough, because it’s not a jumper to change the FSB. Here’s a picture of the jumpersettings in the manual. picture
As you can see, it goes from 16x to 24x. So in theory, it would be possible to use a 2,4Ghz (18 x 133), choose an FSB of 133 (another jumper) and select a 24x multi, which would run the CPU at 3,2Ghz on a 133Mhz bus. Somehow I doubt this is possible :slight_smile:
But this brings me back to my initial question; why that jumper?


#5

To get us/you excited I suppose. There was a time when this was needed. But because the CPU’s are locked this feature is useless.


#6

As Stoner said, there are indeed CPU’s without mp lock available. Most of them are made for testing purposes (so called engineering samples) and handed over to hardware manufacturers…