128 bit memory question

[jakeroberts]

Hello, I went to my local Mac dealer today and bought a 512 stick of ram. It doesn't look like the one that I had already but system profiler reports them the same. Is there a way to tell if its running in 128 bit mode now?

 

[cwa107]

Hello, I went to my local Mac dealer today and bought a 512 stick of ram. It doesn't look like the one that I had already but system profiler reports them the same. Is there a way to tell if its running in 128 bit mode now?

I think you might be confusing bandwidth with different bus modes (i.e. dual channel). The bandwidth of the memory bus in your machine is fixed, however, if you have two identically matched modules, it will run in dual-channel mode. If the modules are different (differing number of chips on each module), it will not run in dual-channel mode.

There is no easy way to match modules without buying identical modules at the same time (I don't believe the vendor matters, as long as the module is configured in the same way).

 

[Alexis]

Stick two identical DDRII 667Mhz DIMMs in there and if OS X detects them, they'll be running at full speed.

 

[jakeroberts]

yes dual channel is what I mean. Is there a way to tell if this is working? A terminal command I can type or something?


I should add that I am running an early G5 (no isight).

 

[cwa107]

yes dual channel is what I mean. Is there a way to tell if this is working? A terminal command I can type or something?


I should add that I am running an early G5 (no isight).

Not that I know of, but I can assure you that if the modules have different numbers of chips on them, you will not be running in dual-channel. The modules must be identical in configuration (but not necessarily the same brand).

 

[jakeroberts]

Thanks