[l008com]

I know that PC133 ram works in 100 and 66 MHz machines right. What about this new DDR ram, PC2100 and PC2700, does that stuff work in PC133, 100 and 66 as well? If so, that would make keeping amounts of RAM in stock much easier for some.

[Mr. Blur]

Originally posted by l008com:
I know that PC133 ram works in 100 and 66 MHz machines right. What about this new DDR ram, PC2100 and PC2700, does that stuff work in PC133, 100 and 66 as well? If so, that would make keeping amounts of RAM in stock much easier for some.

in *some* cases pc133 ram will work in slower dimm slots (again, mostly on the peecee side is where the maybe's come in...). the ddr stuff will not - pc100 or 133 has 168 pins, ddr has 184

[l008com]

Oh, well i was talking Mac only anyway... so what about DDR's, are they backwards compatible on their own?

[CIA]

(DDR is a diffent story, more on that later...)
Much like IDE hard drives slow down to match the speed of it's controller card, nearly all DRAM chips out today will do the same to match the bus of the host computer. PC66, PC100, PC133, PC150, (I know, PC150 isn't used in any macs, but it fits the mold here) will ALL slow down to match the speed of whatever computer they are in. I have a beige G3, normally takes PC66 ram, running 3 PC133 chips. PC133 was cheaper when I got them, and they all are running at PC66 with no problems. DDR ram is different, and I can't comment on that. But don't make it sound like it's rare to get a PC100 chip running in a PC66 slot. Granted, UPclocking ram is not easy. It's not cost effective these days either to get PC66 RAM running at PC100 speeds.

[TheMosco]

Originally posted by l008com:
Oh, well i was talking Mac only anyway... so what about DDR's, are they backwards compatible on their own?

yes, you can use PC2700 memory in a PC2100 ram slot.