HP Probook 4525s memory clock

[martynus]

Hi guys.

Recently I made an upgrade to my Probook 4525s. I decided to add another ram 4GB 1333MHz PC3-10600 module to the one existing (Samsung M471B5273CH0-CH9). After I did so I found out that both modules together run @ clock 1066MHz and basic timings just as if only one module is installed in the system.

So far I have tried to exchange with other 2 independent modules (one samsung and one SKhynix) where both were 1600MHz PC3-12800 spec but the system is still running @ 1066MHz.

The spec sheet for Probook 4525s says it supports 1066 and 1333MHz. But it never runs 1333MHz. Nor with 1333 specd module, nor with 1600 specd.

Any thoughts on this matter ?

Mine is running AMD Phenom II P960 CPU with AMD HD5470 discrete graphics.

[Huffer]

If you run just the original DDR3-1333 Samsung module what clock speed is registered?

[Paul_Tikkanen · Accepted solution]

Hi:

This link states the processor will only run the memory at 1066 MHz.

You can install backward compatible memory (1600 or 1333 MHz), but it will only run at 1066 MHz.

http://www.cpu-world.com/CPUs/K10/AMD-Phenom%20II%20Quad-Core%20Mobile%20P960%20-%20HMP960SGR42GM.ht...

Memory controller

The number of controllers: 1 Memory channels: 2 Supported memory: DDR3-1066, DDR3L-1066 Maximum memory bandwidth (GB/s): 17.1

[martynus]

It runs 1066MHz ...

[Huffer]

I think @Paul_Tikkanen is right then. The best you can do by adding a chip is to make sure it runs in dual channel mode which makes the memory work a bit faster and better at the same clock speed. To do that, the 2 modules need to be as identical as possible. 

[martynus]

I think he is right too.

Of course I run 2x4GB of exact same 1333mhz Samsung modules right now. It is a bit faster in dual channel, indeed (for example 5,9 -> 7,1 in win7 experience index benchmark). But I somehow missed to check at the CPU side.

Thanks for your inputs guys.

[Paul_Tikkanen]

You're very welcome.

A rule of thumb is that the memory speed can never run faster than the processor FSB.

That is definitely true for all Intel processors.