memory speed vs. FSB speed?

[GasX]

My Asus A7V uses a 133MHz memory speed at an FSB of 100.

Would an Abit BH6 use a 100MHz mem speed at 66MHz FSB?

If so, then does the mem speed become 133Mhz if you O/C the FSB to 100?

 

[Brylord]

Sorry it doesn't work that way. BX boards have the FSB and Memory bus linked together. On the other hand VIA chipsets allow you to change your FSB and your Memory speeds somewhat indepently. For example if you over clock a 300A from 66MHZ to 100MHZ FSB your memory will go from 66 MHZ to 100 MHZ. Via is different it allows you to run the processor at 100 MHz and then select if you want to run the Memory at the same or a different speed.

 

[weshuang]

I've read that the memory speed in and of itself doesn't matter much. Why would you want to set the memory speed higher and therefore require more expensive memory? Or is the purpose to set the memory lower?

 

[Brylord]

I can notice a difference in a machine running at 133MHz vs. 100MHz in the memory. There is at least a 1/3 increase in performance. While going to CAS 2 over CAS 3 is only 10-15% of an increase. Granted I wouldn't advise someone go out and buy new RAM just to run at 133 MHz (well...maybe I did, but if you can run your system at 133 MHz over 100MHz you'd be foolish to pass up the speed increase.

 

[weshuang]

OK, good enough for me. With memory so cheap these days, its hard to think twice about it.

I read somewhere that buying pc150 ram doesn't make sense, because DDR ram is an emerging standard that will win. What do you think?

 

[Brylord]

Well...If I had a system that would run at 150 MHz or better I might think about it. By run I mean not just post there once, I mean run stable all the time. Not many of those. So I think 150 MHz SDRAM isn't very practical at this point. So far though it seems DDR isn't that great of a performer (better than PC133 but not by the margins we hoped for). However, I understand it is cheaper to make than SDRAM so it will become the standard I'd say. I'd wouldn't invest a lot into RAM until there is a standard. I have 3 machines at home and put 128MB in two and 250MB in one. I only run my systems at 133 MHz because that is all the PCI bus will handle without doing wierd things. Problem with DDR though is there are only a handle of boards that run it and they are expensive. I'm sure that will all change soon enough as more products are released.