P4 DDR using pc1600 DDR ram only??

[BDSM]

I was just thinking.. Since the p4 is on a 100mhz bus only..
Wouldn't that mean that it would have to use pc1600 ram only? Or is the memory frequency assynchronous to the FSB? Because if it ain't it would make very good sense that Intel releases the 845 chipset with sdram support only first, since pc1600, from what I've been able to figure out yields about zero performance improvement over pc133 memory!
But then again.. If the p4 can't use 133mhz DDR then again it won't be able to make use of anything higher than old pc100 sdram either!

Am I right about any of this? In case I am it would be bad news for those who are waiting to use sdram/ddr with the p4, at leat performance wise.

 

[Cutepunk]

You are correct. i845 will only support PC1600 which means even if you use PC2100 DDR SDRAM, it will work as PC1600. By the way, Northwood will be upgraded to 533MHz (133QDR) FSB, so it would be good idea to get PC2100 sticks if you want to recycle it.

About the performance, there will be some improvement over PC133. P4 utilizes memory bandwidth very well. The only reason why PC1600 didn't show any improvement over PC133 is that... Athlon is not a bandwidth-hungry CPU. It doesn't utilize bandwidth as well as P4 does.

 

[Athlon4all]

Yeah, but still PC1600 is only 1/2 bandwidth of Dual PC800 so performance is questionable