Thinkpads Forum

The -4AU 600E I have came with a 128mb pc133MHz module, aside from the 32mb on the computer.

Therefore, I recently ordered another inexpensive 128mb module, also pc133 to be compatible. However, I know the FSB of the 600E is 66MHz...so both these modules will apparently be clocked down to 66; The current 128mb module is already clocked down, per Powerleap, which shows 67MHz.

The point:

I am going to add the other 128mb. If the onboard 32mb is disabled in the BIOS, perhaps the remaining 256mb--automatically reduced to 100MHz (still higher than 66)--will be better than 288 at 66.

So...is this true? Is there a linear correlation between fsb speed and "effective RAM"?

im not really the person to be answering this question, but im sure i read in one of katchs threads detailing his CPU upgrade on a 600e that benchmarks read higher with the 32mb onboard ram disabled once he had over clocked the bus speed. but this might no apply to an otherwise unmodified machine, here is the thread just in case, but i would try to fix what aint broken to be honest!

http://forum.thinkpads.com/viewtopic.php?t=7427

I think that it will be too close to tell. I'd be interested to know, if you can find a good way to benchmark the difference.

Having said that, I would like to warn you that the PC133 that you just ordered may or may not work. Normally these systems will only take PC66 or PC100 ram.

I am going to add the other 128mb. If the onboard 32mb is disabled in the BIOS, perhaps the remaining 256mb--automatically reduced to 100MHz (still higher than 66)--will be better than 288 at 66.

That is not going to happen. The FSB is dependent on the CPU module. The
PII and PIII MMC-2 modules set the FSB to 66MHz and 100MHz,
respectively, no matter what kind of memory is put in. So if you don't
upgrade the CPU and keep the original PII module, the FSB is still 66MHz and
therefore disabling the onboard RAM has absolutely no effect other than
reducing the total amount of memory.

I have a 600E modified with a P3 500 mhz using two 128mb chips of Micron PC133 ram.

Using CPUBench2003 it had an overall score of 1490 with the 32mb disabled and an overall score of 1492 with the 32mb enabled.

Powerleap says that the FSB is 100mhz. So I assume that the onboard 32mb of ram is able to run at 100mhz rather than the other 256mb of ram clocking down to 66mhz.

I still keep switching back and forth from enabling and disabling the onboard ram but I can't seem to tell much of a difference.

Don't know if this means anything, just thought I'd post my findings.

All right, thanks to you all for the replies.

I'll just keep everything enabled, then...