FSB Northbridge strap question

davethe11

davethe11

davethe11

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hi there

I've just been reading up about the FSB Northbridge strap and have a question.

Apparently the strap is applied when the FSB reaches a certain limit. But I have also seen information about calculating the Northbridge FSB speed:

(default cpu multi / current cpu multi) x current FSB

so, my E2200 has a default multiplier of 11, but I am currently overclocked at 266MHz FSB with a 10 multi, therefore:

(11 / 10) * 266 = 325 Northbridge FSB frequency

Now I've seen that the strap changes when the FSB reaches 400MHz (or 401 for Asus boards apparantly), but is this when the base CPU FSB reaches 400 (mine is at 266 currently) or when the Northbridge FSB frequency reaches 400 (currently at 325)?

hope that all makes sense!
 
I take it this is a question of what to set in the bios for overclocking?

This is how I work out what to use in the bios (Maximus Extreme) depending on what CPU I am using :

Low FSB strap for low FSB CPU's (200/266) 533/800 (like P4's/Celeron's
High FSB strap for high FSB CPU's (333/400) 1066/1333 (like E6750/QX9650)

Or forget about it all and use the Auto setting and set the ram manually to the right speed for the CPU. e.g. lower spectrum for lower FSB CPU's, higher spectrum for high FSB CPU's. But this is dependant on what Ram you are using. Really high clocks might require some ram overclocking.

It's a case of playing around in the bios to see what works, revisions and boards differ slightly in the way they work, or don't.
 
thanks weescott, interesting info. I've noticed that Orthos reports the cpu speed incorectly, it takes the default multiplier of your cpu (mine is 11) and multiplies this by your actual FSB, rather than taking your actual cpu multiplier (mine is currently set to 10), so Orthos tells me my cpu is at 3GHz, where infact it is only at 2.66GHz (approx speeds).

A question about temps if you dont mind, the Asus PC Probe II application reports a temperature of 38 at idle, while coretemp and speedfan report both cores around 27c. I would like to push my cpu to 3GHz but not if the PC Probe applicaion is correct, as CPU temp went up to 57c whilst running Orthos. Is the PC Probe application known to be inacurate? Also, it only gives a single temp (CPU temp) whereas coretemp and speedfan give seperate temps for each core - would this explain the discrepency in any way?
 
Never trust software for temperatures, especially Asus software. Coretemp/speedfan will get you the closest true temperature reading.
 
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