Basic CPU clocking BIOs question

[takeshix]

OK, Im sorta a newbie when it comes to BIOs settings. So I have this old lanparty pro875b motherboard. Right now it has a P4 2.4 GHz in it.

It spec'ed out to run at 533 -800 MHz FSB the CPU clock setting for this would be 133-200 correct?

133 x 4 for the 533 2.4 GHz
200 x 4 for the 800 3.2 GHz

does this sound right? So if i put in the 3.2 GHz I would change the clock speed setting to 200?

Also I understand the different speeds for memory:

DDR266, 133, PC2100
DDR400, 200, PC3200

But is there a setting I need to adjust in the BIOs for which ever I decide to run?

Thanks in advance for any help ^^

 

[o1die]

Just set it to default; that board should run any socket 478 p4, but some later versions may require a bios flash. To be sure, check DFI's archives for "cpu support".

 

[takeshix]

Yea i understand this. But maybe i should just simplify my question, i seem to be having a hard time getting a response.


Is clock speed for 533 FSB 133?


Is clock speed for 800 FSB 200?

Thanks

 

[flyinfinni]

Not exactly. Your base clock will ALWAYS be 133MHz at stock settings. If you are running the 2.4 GHz CPU, it will have a multiplier of 18 (133.3x18=~2399) If you are running the 3.2 GHz CPU, it will have a multiplier of 24 (133.3x24=~3199). The same goes for the FSB. it's just a multiplier difference, not a base clock difference- 533 FSB is a 4x multiplier while the 800 MHz FSB is a 6x multiplier. Upping the base clock from 133 to whatever would technically be an overclock.

 

[takeshix]

So I would "NOT" change the CPU clock setting in the BIOs to 200 if I upgraded to the 3.2 Ghz CPU with 800 FSB? I leave it at 133 no matter what processor i put in it?

 

[flyinfinni]

That is correct. If you change it, you will end up overclocking the CPU, RAM, FSB, etc. All of those components get their clock speed from that main base clock, just having different multipliers. if you bumped your base clock to 200 MHZ, you'd end up pushing your CPU at 4.8 GHz, your FSB at 1.2 GHz, etc. which, without some serious tweaking/voltage adjustments and really good cooling, you'd have some serious problems.

 

[takeshix]

Thank you ^^

 

[delluser1]

Yea i understand this. But maybe i should just simplify my question, i seem to be having a hard time getting a response.


Is clock speed for 533 FSB 133?


Is clock speed for 800 FSB 200?

Thanks

Yes

 

[delluser1]

So I would "NOT" change the CPU clock setting in the BIOs to 200 if I upgraded to the 3.2 Ghz CPU with 800 FSB? I leave it at 133 no matter what processor i put in it?

No , you would not change it, the bios would change it on it's own.

 

[delluser1]

Not exactly. Your base clock will ALWAYS be 133MHz at stock settings. If you are running the 2.4 GHz CPU, it will have a multiplier of 18 (133.3x18=~2399) If you are running the 3.2 GHz CPU, it will have a multiplier of 24 (133.3x24=~3199). The same goes for the FSB. it's just a multiplier difference, not a base clock difference- 533 FSB is a 4x multiplier while the 800 MHz FSB is a 6x multiplier. Upping the base clock from 133 to whatever would technically be an overclock.

You got it right on the 2.4
http://ark.intel.com/Product.aspx?id=27438&processor=&spec-codes=SL67Z,SL684,SL6D7,SL6DV,SL6EF,SL6EU,SL6PC,SL6Q8,SL6RZ,SL6SH,SL79B
But you're off on the 3.2
http://ark.intel.com/Product.aspx?id=27466&processor=540&spec-codes=SL79M,SL7B8,SL7E5,SL7J7,SL7KC,SL7KL,SL7LA,SL7PN,SL88K,SL8K2,SL9C6

It's not a multiplier difference, it's a base clock difference
Base clock x 4 = FSB
133 x 4 = 533
200 x 4 = 800
266 x 4 = 1066
333 x 4 = 1333

Baseclock x multiplier = CPU frequency
133 x 18 = 2.4
200 x 16 = 3.2
266 x 10 = 2.66 ( E6700 )
333 x 9 = 3.0 ( E8400 )

 

[flyinfinni]

You got it right on the 2.4
http://ark.intel.com/Product.aspx?id=27438&processor=&spec-codes=SL67Z,SL684,SL6D7,SL6DV,SL6EF,SL6EU,SL6PC,SL6Q8,SL6RZ,SL6SH,SL79B
But you're off on the 3.2
http://ark.intel.com/Product.aspx?id=27466&processor=540&spec-codes=SL79M,SL7B8,SL7E5,SL7J7,SL7KC,SL7KL,SL7LA,SL7PN,SL88K,SL8K2,SL9C6

It's not a multiplier difference, it's a base clock difference
Base clock x 4 = FSB
133 x 4 = 533
200 x 4 = 800
266 x 4 = 1066
333 x 4 = 1333

Baseclock x multiplier = CPU frequency
133 x 18 = 2.4
200 x 16 = 3.2
266 x 10 = 2.66 ( E6700 )
333 x 9 = 3.0 ( E8400 )

Are you sure this is exactly right? The issue is, if this is the case, then you drop in a faster CPU, it changes your base clock, then your RAM is gonna get cranked as well. The base clock, as far as I know, is just that- the base clock- it never changes unless your change it. Maybe there is an extra multiplier in there that gets the bus speed and the FSB speed, but every Motherboard I've ever had has had a single base clock, no matter what CPU you drop in. I guess I've never had a P4 (always had AMD up until my current i5 750) but never seen anything other that a 200 MHz (AMD chips) or 133 MHz (Intel chips) base clock unless it was overclocked.

 

[delluser1]

This explains it much better than I could
http://en.wikipedia.org/wiki/Front-side_bus

 

[flyinfinni]

That doesn't really get at what I was confused about- I understand that stuff. Where I'm confused is that, as far as I know, all Intel CPU's I've ever used/known have had a 133 MHz base clock, all the AMD's have had a 200 MHz base clock, whereas the FSB rate and CPU were multiplied off of this to get their final clock rates (which I know they are). What your previous post says is that the higher clocked P4's actually use a different base clock (not FSB) rate, which I thought was pretty static across lines of CPUs and generated BY THE MOBO, and thus not changed when you change CPU's. Meaning, if I had a P4 at 2.4 (like the OP), I have a base clock of 133, an FSB at 533 (x4 multi), a CPU at 2.4 (x18), and ram at 400 (x3). If I drop in a P4 3.2, does the base clock go to 200, giving me an FSB at 800 (x4), a CPU at 3.2 (x16), and RAM at 600 (x3)? CPU multi is locked, FSB is tied to what the CPU can do, but the RAM is separate. I've never heard of the RAM multi changing when you drop in a different CPU, which it would HAVE to do if what you are saying is true. I guess it seems to me what would have to happen is that there must also be a BUS speed (not FSB, not Base clock) that determines the CPU speed for the P4s. Meaning, I still have the base clock of 133 no matter what CPU I have installed, but rather with the 2.4 GHz CPU, the Bus and the Base clock are 1x multi, but dropping in the 3.2 GHz CPU, the bus and Base clock have a 1.5x multi. Unless the P4's are a different from everything I've messed with somehow, but yeah... I hope this makes sense to anyone else who reads it

 

[delluser1]

Go back a reread the Memory section from the Wiki link, be sure to click on the memory divider link and read it as well.