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Old 18-03-09, 08:52 PM
ahile ahile is offline
Join Date: Feb 2009
Posts: 5
newb question about my DDR2 1066MHz RAM - reported at only 750Mhz

ok so i know that this is a newb question but i`m trying to uderstand so thx in advance for u`r help.


i have a dual core E6750 (prety old i know) - standard it has its clock set at 333 so that means the fsb should be smt like 333x4

and the standard multiplier is 8 so it is at 333x8- 2666 or smt

1. now back to my problem, when i leave it on standard (333) the Memory Mhz is set to 800.

as I raise the 333 up to 349 the Memory Mhz keeps going at 800+ BUT once i reach 350, the Memory Mhz goes back to 700Mhz and only at 400 it is back at 800Mhz again (that means overcloking the CPU at 3200)

atm i use it at 375 and i rly don`t get it why the Memory Mhz is 750 ... (altho when i use the standard 333 it is at 800Mhz ???)

i thought with DDR2 Memory u simply muliply the Fsb/Clock with 2 ...

could some1 pls explain to me in detail how the memory Mhz works in corelation with the fsb/clock - whatever it is called



p.s. btw the standard 333 is called FSB or Clock cuz as far as i know it is Clock but i may be mistaking cuz on my MB bios it is called FSB.

any link that can help would be greatelly appreciated


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Old 18-03-09, 09:17 PM
Ham Ham is offline
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Join Date: Dec 2005
Posts: 6,981
Your motherboard is compensating for higher FSB by using different dividers and straps, trying to maintain the ram clock at 800 (or as close to as possible).

To remedy this, you just need to adjust your settings to compensate. 333 strap should be fine, and which ever divider your board has that will allow you to get as close to 1066 as you can. These settings can be called numerous things in the bios. Dram Speed is a quite common tag.
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Old 18-03-09, 09:27 PM
ahile ahile is offline
Join Date: Feb 2009
Posts: 5
maybe i was not so clear above, when i was referring to the 333 i was talking about the CPU clok / fsb - as the memory is set automaticly with the CPU

i can disable this function but then i have to set a hell lot of other things regaring Memory and i don`t wanna get into that.

what i don`t get is why the Memory Mhz is 800+ until the CPU fsb is 349, then at 350 it resets back to 700 Mhz and only gets back to 800 Mhz when the CPU FSB is at 400 (aka 3200 Mhz)

why can`t i have the Memory at 800 Mhz and the CPU at 3000 Mhz (that means 375 Fsb)

is there any way to do that ? - maybe my question seems stupid but pls try to explain to some1 with not so much experience

thx a lot !
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Old 18-03-09, 09:36 PM
°TheMadDutchDude° °TheMadDutchDude° is offline
Join Date: Sep 2008
Posts: 840
As Ham said, you have to change your strap or divider.

Once you hit the 350 barrier, your motherboard is turning back to a 1:1 ratio which means when you're on 350FSB, your RAM is set to run at 350 (700 effective) and therefore in order to reach your 1066 you're going to have to be running at 533FSB (do not attempt it at all!)

In order to change this, look for the ratios. Look for one that will give you the closest value to your stock RAM settings and pick that one. I think 1:1.25 or 1:1.5 should be it.

As for the straps, choose 333 and your RAM should appear as a selectable 1066 or close to that digit.
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Old 18-03-09, 09:42 PM
Ham Ham is offline
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Join Date: Dec 2005
Posts: 6,981
Allowing to the board to set the ram speed via the cpu is what's causing this behaviour.

There is a setting known as the strap (Sometimes called northbridge strap or FSB strap) which set up sub timings for the board. The options for this setting are 200, 266, 333 or 400 on most 775 boards. Which strap you use will determine what speeds you can set your ram too. Ram speed is then set using one of the dividers that the strap setting allows.

When your changing your FSB, the motherboard, as it is set up now, is trying to keep you memory as close to 800mhz as the strap and dividers allow. As you raise the FSB, the memory clock will rise with it, to the point where a different divider (on either the same or a different strap) will be closer to 800mhz. The board will adjust your settings, to stay close to that 800 mark.

To overcome this, you need set manually the divider you want. With a few boards leaving the strap on Auto will result in every divider being shown.

What motherboard are you using?
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Old 18-04-09, 06:58 PM
xX_o2_Xx xX_o2_Xx is offline
Join Date: Apr 2009
Posts: 22
sounds to me like the RAM timings may be out, with your motherboard could you manually alter the timings?

or is your board definatly compatible with 1066 ram?, it may be that it supports a maximum of 800mhz like my MSI board
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