QUOTE(steventan85 @ Jan 3 2009, 01:12 PM)
set it at bios d and it show 533mhz .... so i need to set either 4+ or auto to get 800mhz

Your physical ram of 800Mhz rated speed is now operating at 533Mhz.
Now what is the fsb/ram ratio now??? That depends on what is your fsb as indicated in your bios/cpuz/occt etc now!
Scenario 1:
cpuz/bios fsb is 266Mhz
Then your fsb/ram ratio is 1:1 (equivalent to spd thing 2.0) , because your DDR 2 ram speed is 2 x fsb giving you 533 Mhz.
Scenario 2:
cpuz/bios fsb is showing 222Mhz
Then your fsb/ram ratio now is 5:6( equinalent to spd thing 2.4).......... giving you ram speed of 533Mhz also .
Scenario 3 :
cpuz/bios fsb is showing 213Mhz
Then your fsb/ram rato is now 4:5(equivalent to spd thing 2.50), giving you DDR 2 ram speed of 533Mhz.
In all the above scenarios, your physical rams of rated speed s of 667Mhz or 800Mhz or xxxMhz are NOT operating at their respective speeds of 667/800/xxxMhz.They all operate at 533Mhz!!
The question now is what is your cpuz/bios fsb??? Having identified your actual fsb now,and select the available fsb/ram ratio in your bios, then only we can talk about what is the operating speed in Mhz of your 800Mhz ram (rated speed)
In scenarios 2 and 3 above, your 800Mhz rated speed ram can NEVER operate at a DDR2 frequency of 800Mhz simply because the 'suitable ratio of say 5:9 fsb/ram ratio is NOT available in typical Motherboards.
Hope it helps.
This post has been edited by zeng: Jan 3 2009, 11:54 PM