Pentium processor speed

[Bad Wind]

I've just installed a new Pentium 2.8GHz processor in my computer, but its
only showing as 2.1GHz in BIOS and Belarc Advisor. (2.8 in Device Manager
though) Any ideas? Would a BIOS upgrade solve this or is it something else?
Or perhaps a XP reinstall?

P4 2.8/533/512 Socket 478

Thanks

 

[Yves Leclerc]

Have you checked the processor for tampering?? There has be processor that
were "remarked" to higher speeds and sold as higher speed processors. This
is considerd as fraud.

 

[Jason Tsang]

Check to make sure your FSB speed is set correctly. It sounds like it is
set wrong.

You may also need a bios update so that the appropriate microcode for your
processor can be applied.

 

[David Hollway [MVP]]

I've just installed a new Pentium 2.8GHz processor in my computer, but its
only showing as 2.1GHz in BIOS and Belarc Advisor. (2.8 in Device Manager
though) Any ideas? Would a BIOS upgrade solve this or is it something
else? Or perhaps a XP reinstall?

P4 2.8/533/512 Socket 478

Hi,

Sounds like your board is set to - or perhaps, only supports - 400MHz bus
speed. The processor speed is calculated as follows:

[bus speed / 4] times [multiplier] = core speed

The reason that the bus speed is divided by 4 is that the Pentium 4 bus is
"quad-pumped" - in other words, it's clocked at 100 or 133 or 200MHz, but
transfers data at 400, 533 or 800MHz.
The multiplier is fixed and can't be altered, and for the 2.8GHz/533
processor is set to 21 (2800/133 = 21). However, what would you get if you
ran that processor on a 400MHz (OK, 4x 100MHz) bus? Yes, 100 x 21 = 2100MHz,
which is what you have.

In order to further confuse things, the processor's "real" speed is burned
into the processor at manufacture time and is read by the OS as part of
processor identification. That's why Windows XP, in the My Computer -->
Properties dialog box, will report something like:

Genuine
Intel(R) CPU 2.8GHz
2.1GHz, 512MB of RAM

The first two lines are the "CPUID" data, read straight from the processor.
The third line is what Windows has actually measured. In the above example,
it shows a 2.8GHz processor that's only running at 2.1GHz. The idea of
"branding" the true speed into the processor is handy; it's primarily
intended to foil professional re-markers and unscrupulous PC sellers
attempting to sell overclocked PCs to unwitting customers, but it's also
useful in the reverse scenario - for seeing what speed your CPU is really
running at and detecting inadvertent "underclocking".

So.. my advice is, check your motherboard and BIOS. First, be sure that the
board and chipset actually support the 533MHz system bus; older Intel 850
and 845 chipsets variants didn't. Next, assuming that the answer to that one
is "yes", check the documentation for your board and figure out how to put
it into 533MHz bus mode. It might be via a switch in the BIOS, or a jumper
on the board - on all the boards I've seen it's automatic, so I can't be
more specific.

Having got the board to 533MHz, you should see the full 2.8GHz speed, and
you shouldn't have to re-install Windows XP; processor changes are normally
transparent to the OS.

Hope this helps..

 

[Bad Wind]

Thanks for your help.

The bus speed was set to 100 in the BIOS and I had to increase it to 133.
Everything now appears to be running OK.

I just hope that the SDRAM can keep up with this increased bus speed.

Now to test it out with some video conversions....

Thanks again to all who contributed.

I've just installed a new Pentium 2.8GHz processor in my computer, but
its only showing as 2.1GHz in BIOS and Belarc Advisor. (2.8 in Device
Manager though) Any ideas? Would a BIOS upgrade solve this or is it
something else? Or perhaps a XP reinstall?

P4 2.8/533/512 Socket 478

Hi,

Sounds like your board is set to - or perhaps, only supports - 400MHz bus
speed. The processor speed is calculated as follows:

[bus speed / 4] times [multiplier] = core speed

The reason that the bus speed is divided by 4 is that the Pentium 4 bus is
"quad-pumped" - in other words, it's clocked at 100 or 133 or 200MHz, but
transfers data at 400, 533 or 800MHz.
The multiplier is fixed and can't be altered, and for the 2.8GHz/533
processor is set to 21 (2800/133 = 21). However, what would you get if you
ran that processor on a 400MHz (OK, 4x 100MHz) bus? Yes, 100 x 21 =
2100MHz, which is what you have.

In order to further confuse things, the processor's "real" speed is burned
into the processor at manufacture time and is read by the OS as part of
processor identification. That's why Windows XP, in the My Computer -->
Properties dialog box, will report something like:

Genuine
Intel(R) CPU 2.8GHz
2.1GHz, 512MB of RAM

The first two lines are the "CPUID" data, read straight from the
processor. The third line is what Windows has actually measured. In the
above example, it shows a 2.8GHz processor that's only running at 2.1GHz.
The idea of "branding" the true speed into the processor is handy; it's
primarily intended to foil professional re-markers and unscrupulous PC
sellers attempting to sell overclocked PCs to unwitting customers, but
it's also useful in the reverse scenario - for seeing what speed your CPU
is really running at and detecting inadvertent "underclocking".

So.. my advice is, check your motherboard and BIOS. First, be sure that
the board and chipset actually support the 533MHz system bus; older Intel
850 and 845 chipsets variants didn't. Next, assuming that the answer to
that one is "yes", check the documentation for your board and figure out
how to put it into 533MHz bus mode. It might be via a switch in the BIOS,
or a jumper on the board - on all the boards I've seen it's automatic, so
I can't be more specific.

Having got the board to 533MHz, you should see the full 2.8GHz speed, and
you shouldn't have to re-install Windows XP; processor changes are
normally transparent to the OS.

Hope this helps..