P4B - cpu question

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neon

I have a P4B with a 1.5 in it. What is the max the board will support?
I need a few extra ponies to deal with video.

thanks in advance
 
I have a P4B with a 1.5 in it. What is the max the board will support?
I need a few extra ponies to deal with video.

thanks in advance

Certainly a 2.4 according to the manual (an old maual), and no reason
why not a 3.0c. Northwood - don't try fitting a Prescott
 
Certainly a 2.4 according to the manual (an old maual), and no reason
why not a 3.0c. Northwood - don't try fitting a Prescott

This web page has the answer:
http://www.asus.com.tw/support/cpusupport/cpusupport.aspx

Celeron 1.7 GHz(400 MHz FSB) ALL 1010  
Celeron 1.8 GHz(400 MHz FSB) ALL 1010  
Celeron 2.0 GHz(400 MHz FSB) ALL 1012  
Celeron 2.1 GHz(400 MHz FSB) ALL 1012  
Celeron 2.2 GHz(400 MHz FSB) ALL 1012  
Celeron 2.3 GHz(400 MHz FSB) ALL 1013.001  
Celeron 2.4 GHz(400 MHz FSB) ALL 1013.001  
Celeron 2.5 GHz(400 MHz FSB) ALL 1013.002  
Celeron 2.6 GHz(400 MHz FSB) ALL 1013.002  
Celeron 2.7 GHz(400 MHz FSB) ALL 1013.004  
Celeron 2.8 GHz(400 MHz FSB) ALL 1013.004  
P4-1.4 GHz(Socket478)(400 MHz FSB) ALL ALL  
P4-1.5 GHz(Socket478)(400 MHz FSB) ALL ALL  
P4-1.6A GHz(Socket478)(400 MHz FSB) ALL 1007  
P4-1.6 GHz(Socket478)(400 MHz FSB) ALL ALL  
P4-1.7 GHz(Socket478)(400 MHz FSB) ALL ALL  
P4-1.8A GHz(Socket478)(400 MHz FSB) ALL 1007  
P4-1.8 GHz(Socket478)(400 MHz FSB) ALL ALL  
P4-1.9 GHz(Socket478)(400 MHz FSB) ALL ALL  
P4-2A GHz(Socket478)(400 MHz FSB) ALL 1007  
P4-2 GHz(Socket478)(400 MHz FSB) ALL ALL  
P4-2.20 GHz(400 MHz FSB) ALL 1007  
P4-2.40 GHz(400 MHz FSB) ALL 1007  
P4-2.50 GHz(400 MHz FSB) ALL 1011  
P4-2.60 GHz(400 MHz FSB) ALL 1011  

What this means, is no processors with Prescott in the name.
No processors with 1MB cache or "90nm" in the details. No FSB533
or FSB800 processors. (I don't know whether the board is
smart enough to handle a FSB533 processor - the board has
certainly been overclocked to FSB533, but I don't know if
the BIOS will set the bus automatically to FSB533 for you or
not. You could buy a FSB533 processor, and set the CPU
external frequency to 133MHz to match it, and see what happens.
Check Google to see if it has been done.)

You want a 0.13u 512KB cache Northwood P4. The Celeron would
be a little anemic and a waste of money.

Your main challenge on that board, is memory bandwidth.
Using PC133 CAS2 memory is the best you can do.

I was told when I bought my P4B a while back, that a P4 1.8GHz
was the best practical speed, as with memory bandwidth
starvation, a higher core clock speed wouldn't help. Since
the processor has a 512KB cache, I don't believe that entirely,
and it depends on how much computing can be done in a tight
loop, that determine whether higher speed CPUs will help.

You also have the option of overclocking. The memory ratio
can be set to 1:1 or 3:4. If the processor is at the nominal
FSB of FSB400, then with PC133, you can use the 3:4 ratio.
That is because FSB400 = 4 * CPU_Clock_100MHz, and 100MHz*(4/3)
= PC133. If you then manually set the FSB in the BIOS, by
changing the CPU clock from 100MHz to 133MHz, and change the
ratio of CPU:MEM to 1:1, the processor speed is bumped by 33%,
while the memory speed is 133MHz*(1/1) = PC133. I had planned
on doing that to my P4 1.8a, but never got around to it.

There is an overclocking database here. Not all the entries are
for real, so look at the average overclock or scan the results
to get a feel for what is possible. The 1.8a is Northwood (1.5V
Vcore), for example, and the 1.8 is the older Willemette
(1.75V Vcore).

http://www.cpudatabase.com/CPUdb

In terms of selecting a CPU frequency, for a FSB400 processor,
100MHz is the nominal value. In the part of the manual, where is
describes frequency selection via DIP switches, the nominal switch
setting would be the 100/67/33 value. The 67 is the AGP speed and
the 33 is the PCI speed. As you change the speed setting, notice
the PCI speed changes as well. The PCI bus should not be run above
about 37.5MHz, as disk corruption could result. Sometimes the IDE
bus derives timing from the PCI clock, so that is one reason to
avoid the 120/80/40 setting, for example. If you choose to set the
speed in the BIOS instead, in jumper free mode, keep that in
mind when selecting a frequency. Generally, there will be a couple
of "zones" of frequencies to avoid. The nice multiples, like 100,
133, 166 etc, generally give nice 66/33 numbers for AGP/PCI, but
values slightly below those frequencies could be ones with a PCI
set too high. This is the "divider" effect, where the divider is
not always designed to keep the PCI at a reasonable speed.

Another limitation is how much current the Vcore regulator can
source. This is something to monitor when overclocking. Place a
finger on the MOSFETs and coils next to the processor, and if
the MOSFETs are getting warm, then you must be nearing the limits
of the regulator circuit. Check the regulator circuit when running
at nominal conditions, so you can see how warm they get normally.
If pushed too hard, a MOSFET can exceed its SOA (safe operating
area) and will go into thermal runaway. Only push the frequency
setting on the processor to where the MOSFETs don't burn you - run
Prime95 in "torture test mode" to load the processor while testing,
to simulate a 100% CPU load.

When you go to buy a processor, ask the vendor for either the
Intel order code (like BX80532PC2600D) or the SSPEC (like SL6QR).
You can look up that code on:

http://processorfinder.intel.com

Examine the entry, to make sure it has 512KB cache, the FSB
you want, roughly 1.5V Vcore, and is 0.13u micron geometry. That
tells you that it is a Northwood.

For example, Newegg has a 2.6Ghz/FSB400/512KB OEM processor for
$149. It has order code RK80532PC064512. With an OEM processor,
there isn't a HSF, so you will be reusing the one from your
current processor, or finding a third party HSF rated to cool
a 2.6GHz processor.

HTH,
Paul
 
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