Reading the prepost before my windows XP pro starts I always see my
ram as 266 DDR speed. I have three sticks of 512's DDR 400 from
Samsung. The ram memory does show as 1.5G but I am trying to figure
out why they are not posting up as DDR 400. I am not sure if its to do
with the BIOS or not. My current AmiBIOS is 1002.002
What haven't I done correct?
Does this mean they are only processing at 266 DDR?
Have you tried a utility like CPUZ ? There are a few different
utilities that can give details about your system.
http://www.cpuid.com/cpuz.php
First of all, using three sticks on a dual channel board, will
put you in virtual single channel mode. That cuts memory performance
by at least 30%. Either remove a stick and use a matched pair (one per
channel) or add a fourth stick for two matched pairs.
As I understand it, this happens as a side effect of using the
AI Overclocking feature in the BIOS. It has a tendency to use
the 3:2 divider for RAM. Other than that, you could always have
selected this memory clock manually.
CPU_Clock 200MHz x 4 = FSB800
Memory clock = CPU_Clock x ratio x 2 (for DDR)
= 200MHz x 2/3 x 2 = DDR266
If using a FSB800 processor, selecting a memory speed of
DDR400, selects the 1:1 ratio, and gives the right speed.
If you overclock the CPU by changing the CPU clock to higher
than 200MHz, the memory settings actually represent ratios
and the BIOS doesn't show the memory speed via the actual
selection. At least this is the way it was with early BIOS.
(With so many models of 865/875, this feature isn't the
same on all boards.) For a FSB800 processor, the DDR400
setting selects 1:1 ratio, DDR333 selects 5:4 ratio, DDR266
selects 3:2 ratio (where ratio is CPU:Memory and
CPU_Clock * (Memory / CPU) = Memory_Clock and
Memory_Clock x 2 = Actual_DDR_Rate).
HTH,
Paul
