Issue on the frequency bus and ram with Banias and Dothan

[Nicola]

I have found a T40 a low cost and I bought it only to sell it.
In these days I am tested it in order to know the Centrino's ThinkPad better.

This computer use a Banias 1,5.

I have read of recent that all Pentium M have the multiplier unblocked towards the bottom.
With a software I have set up the fixed frequency at 600, 800, 900, 1000, etc.
This is very positive. My IDEAL THINKPAD works fixed to 600 mhz; but if in some cases I will have to raise the frequency, I will be able to raise it of the indispensable minimum.

But there it is a very weird thing. The ThinkPad with Banias have a RAM PC2100 (133 DDR). But when this T40 normally works (the 1500 mhz) the ram works to 100 mhz.
Why?
Why ThinkPad T40 mounts ram the 133 mhz? In which occasions the ram works to this frequency?

- _ - _ - _ - _ - _ - _ - _ - _ - _ - _ - _ - _ - _ - _ - _ - _ - _ - _

Who possesses a Dothan can test it and they can say we the frequenzy of the CPU/RAM in the normal operation and energetic saving.

SOFTWARE

FOR TO SEE IN REAL TIME THE FREQUENCY OF CPU

cpu z
www.cpuid.com/cpuz.php
you can hold it open while to test the other software

TO CHANGE THE FREQUENZY

RightMark CPU Clock Utility
http://cpu.rightmark.org/products/rmclock.shtml

_____RightMark Gotcha
_____http://cpu.rightmark.org/products/rmgotcha.shtml
_____This sw is in background and records the frequency of the cpu.
_____Much strange, with Banias 1,5 also 400, 200 and 80 mhz.

Notebook Hardware Control
www.pbus-167.com

OTHER SOFTWARE

Crystal Cpuid
CrystalDiskMark
http://crystalmark.info/

You know where to download old version of Centrino Hardware Control CHN? I have only Microsft Inet 1,1 included in Windows XP and for a fast test I do not want to download 22 mb.

[dr_st]

My T42 Dothan:

Full power:

CPU - 1800MHz (18x100), RAM 333MHz (166x2)

Idle (power saving):

CPU - 600MHz (6x100), RAM 333MHz (166x2)

[Nicola]

I have always read that the Dothan works to minimal to 800 mhz.

My T42 Dothan:

Full power:

CPU - 1800MHz (18x100), RAM 333MHz (166x2)

Idle (power saving):

CPU - 600MHz (6x100), RAM 333MHz (166x2)

18X100 is ram to 100
6x100 is ram to 100

When your ram works to 166 mhz?

[dr_st]

I have always read that the Dothan works to minimal to 800 mhz.

Depends on the FSB. In T43 (133MHz FSB) minimal is 800. In T42 (100MHz FSB) minimal is 600.

18X100 is ram to 100
6x100 is ram to 100

You are confusing RAM with FSB. FSB is 100MHz, RAM is 166MHz.

[Nicola]

The chip-set 855pm supports alone FSB 400 (100x4) and the system with ram 133 (and 166) must have an asynchronous bus.
Therefore cpu at 800 mhz the multiplier would have to be set up 6 and not 8.

cpu 800 ram 133 = 133 x 6 = 800

If instead cpu 800 ram 100 = 100 x 6 = 800

then what mounts never the ram pc2100?

[dr_st]

Multiplier is CPU speed / FSB, not CPU speed / RAM.

Yes, the RAM is asynchronous with the FSB in the 855PM chipset.

[sktn77a]

Its very difficult to understand what the issue/question is here, but it seems to relate to Speedstep control of the CPU speed vs memory bus speed (?) If I recall correctly, with the 855GM chipset, the memory bus speed is fixed and independent of the FSB speed.

[Nicola]

the RAM is asynchronous with the FSB in the 855PM chipset.

If I recall correctly, with the 855GM chipset, the memory bus speed is fixed and independent of the FSB speed.

Exactly! Therefore the sw they would have to say "ram = 133 mhz" or "ram = 166 mhz to me".
Instead in all the tests that I have made the ram it always works to 100 mhz, like the bus.

[FTC]

Nicola,

FSB in Banias cores is always 400 (100x4) Mhz.
FSB in Dothans is either 400 (100x4) or 533 (133x4). (it is quadpumped, that is why of the 4x). 7x0 Dothans are 533 and 7x5 dothans are 400.

The final processor frequency is always FSB*multiplier
The minimum multiplier (in Banias AND Dothan CPUs) is 6x, so the minimum frequency is 6x100=600 or 6x133=800 depending on whether you have a 533 or 400 core.

Ram can be up to 166Mhz DDR in these machines (T40..T42s). It is asynchronous to the FSB and depends more on the chipset. But RAM is usually always running at a fixed speed. In T40s it runs at PC2100 Specs (133 Mhz*8 bytes width*2 since DDR)=2128 MB/sec. T42s ... run PC2700 RAM (166Mhz * 8 bytes width * 2 DDR) = 2656MB/sec.

I am unsure but suspect that if you put PC2700 RAM in a T40 (and all banks are PC2700), it will most likely also run it at 166Mhz...

There is NO WAY you can run your RAM at 100Mhz ... unless you have installed PC1600 SODIMMS (which I am not sure they exist and/or are supported anyways)

So, If an utility reports your RAM running at 100Mhz :
- Either you are looking at the FSB setting ... or
- The utility is misleading you

[awolfe63]

I am unsure but suspect that if you put PC2700 RAM in a T40 (and all banks are PC2700), it will most likely also run it at 166Mhz...

Nope. PC2700 RAM in a T40 runs at PC2100 speed. Otherwise, it works fine.

[Nicola]

My error. I looked at bus speed and Rated FSB (100 and 400). I never saw the speed of the ram.

You be able to advise me software that it show the speed of the ram? There are utility that lower this speed?

[awolfe63]

I sometimes use memtest86+. CPU-z will also tell you.

Google either.

[Nicola]

http://www.memtest.org/#downiso
I do not understand how to make it work. It is not a normal sw.

I read that the chip-set 855pm support DDR266/200 and second revision support also DDR333.
Then a lot probably can be lowered the frequency of the ram to 100 mhz (DDR200) only with software.