Confused on Memory Speed/Naming

[kagy600]

From my understanding (DDR2)

PC2-5300 = 667mhz which is 2x333mhz
PC2-6400 = 800mhz which is 2x400mhz
PC2-8500 = 1066mhz which is 2x533mhz

Intel's C2D and C2Q use quad-pumped FSB which is;
800 (4x200mhz) 1066 (4x266mhz) 1333 (4x333mhz)

The most recent Anandtech Review got me really confused by switching back and forth between saying ram DDR2-1066 and CPU's at 1066. If you are running your CPU at 800mhz FSB it is effectively 4x200mhz as well as 1333mhz FSB which is 4x333. Yet they were saying that their PC2-8888C4 ram at 1250mhz (2x625mhz) could NOT run at CPU 1333FSB...


Hopefully I didn't confuse you all, but I am finding a hard time understanding this article/review (http://www.anandtech.com/memory/showdoc.aspx?i=2996&p=1).


Thanks in Advance

 

[myocardia]

What's not to understand? That awesome Corsair Corsair Dominator will run up to 625 Mhz/1250 DDR, but it won't do 667 Mhz/1333 DDR. That's why they didn't/couldn't test it at DDR(2)1333.

 

[kagy600]

See thats the problem....

It doesnt seem like they are testing at DDR speeds of 1333 or 1500 (667mhz and 750mhz respectively)... unless I am mistaken. On the graphs of page 4, memory 1500 they have (370x8) which represents the CPU settings. That is 370mhz not 750mhz FSB...

Also quote 2nd page "...both powered by an Intel X6800 processor running at an 8x1333 FSB (333 quad pumped). All that was required to do this was up the base CPU bus to 333, and lowering the default multiplier to 8 (from 11). We did not need to make any changes to CPU voltage and left it at default settings. Due to issues with memory ratios on the P965 we were forced to use 10x266 timings for comparison on that chipset. The P965 was not designed for 1333 FSB speed, so when 1333 is set the available memory ratios do not allow comparison at standard memory speeds..."

They were unable to run a p965 at 333mhz FSB?

EDIT:
Well that quote above also clearly states about memory ratios.... so it seems like all of their testing was done on a 1:2 ratio then? only way i can see it working out..

I guess my mind is set on always doing 1:1

 

[myocardia]

Yeah, they just used memory ratios/mulitipliers. Not only are there no motherboards that will run at a 667 Mhz FSB, there also are no processors that will do it, at least for now.

 

[kojiro82]

I was wondering the same thing as the OP.
Only way I see it is CPU FSB at 333Mhz (x4) and CPURAM ratio of 1:2.
I generally don't see this kind of selection in our current overclocks since we're generally trying to pump out faster clock speeds with low latencies...
So is that correct? Anandtech review using 333MHz, CPU mult = 8, and CPURAM at 1:2?