[nylug-talk] Any way to tell memory speed from command line?

[jh]

David Rosenstrauch wrote:
>> Correct me if I'm wrong (I usually am): I thought the memory speed had 
>> to match the FSB speed, so wouldn't they be the same?
>>
>> - Allen
> 
> 
> I really don't know.  I have to admit, my knowledge is weak in this area.
> 
> According to Dell (and Crucial) this box should take PC2700 266MHz.  But 
> I suspect that the box shipped with PC2100 266MHz.
> 
> However, (unless I misunderstood) according to Alex, 2.1 GB/sec. is the 
> max for that bus speed.  Makes me wonder, then, why both web sites 
> suggest PC2700 for that box.
> 
> Very puzzling ...
> 
First, see this:

http://en.wikipedia.org/wiki/DDR_SDRAM

There is no such thing as PC2700 that runs at 266mhz.

A few things to keep in mind:

* Some chipsets allow async memory access - so that the memory speed and 
the FSB don't have to match.

* DDR is backwards compatible. You can stick PC3200 in there and it'll 
be fine (and may be useful in another context). For example, my everyday 
box is a P4 2.4ghz with 533mhz FSB. Also a Dell. I stuck in generic 
PC3200 to upgrade, and all is well. Plus, it'll be fine in the AMD box 
that I intend to build (waiting for the price of the "old" chips to 
totally decline).

* You only need memory as fast as the CPU needs it to be. If this is an 
old Pentium IV or Celeron, it probably has a 400mhz FSB (really 100mhz 
x4), so PC1600 or above would be suitable. If it has a 533mhz FSB, then 
PC2100 or above is suitable. If an 800mhz FSB, then PC3200 is suitable.

What does the dmesg say in regards to the chipset and CPU?

jh