What speed is my RAM running?

[David9799]

My system
E6600
P5W DH newest bios

I have this ram

http://www.newegg.com/Product/Produc...82E16820145566

With my system at stock it should run at 800Mhz and thats what it says in the bios but when i OC my E6600 to say (350x9) = 3150 the bios will have 700Mhz and 875Mhz and of course more i have tryed 875Mhz and my pc wont boot but at 700Mhz it does.

What i don't understand is why is the Mhz going down when i OC? E6600 at stock runs 800mhz ram and when OC to 3150 it runs at 700Mhz thats all my pc will boot up at anyway.

btw why cant you move the dram frequency up little by little untill you can find what your RAM can handle? The bios only lets you pick a few.

[Vulcan]

I think you need to find a C2D overclocking guide. This is basic stuff.

http://forumz.tomshardware.com/hardw...ict197995.html

[Bloodshedder]

Basically, your RAM will run at 2*FSB*divider.

When you first go into BIOS (with Spread Spectrum disabled) at stock (266 FSB) and you select a DRAM Frequency of 533 that is a 1:1 divider. FSB (266)*2 = DRAM Frequency (533). Now as you scale the FSB up the DRAM Frequency will scall up accordingly. At 350 FSB the DRAM Frequency would be DDR700 ((350*2)*1/1)

If you had selected a DRAM Frequency of 667 at 266 FSB that would be a 4:5 divider, and again, as you scale up FSB the DRAM Frequency will scale up accordingly. So at 350 FSB your RAM would be running at DDR875 ((350*2)*5/4)).

If you had selected a DRAM Frequency of 800 at 266 FSB that would be a 2:3 divider, and again, as you scale up FSB the DRAM Frequency will scale up accordingly. So at 350 FSB your RAM would be running at DDR1050 ((350*2)*3/2)).

Does that clear up what you observed?

[David9799]

Basically, your RAM will run at 2*FSB*divider.

When you first go into BIOS (with Spread Spectrum disabled) at stock (266 FSB) and you select a DRAM Frequency of 533 that is a 1:1 divider. FSB (266)*2 = DRAM Frequency (533). Now as you scale the FSB up the DRAM Frequency will scall up accordingly. At 350 FSB the DRAM Frequency would be DDR700 ((350*2)*1/1)

If you had selected a DRAM Frequency of 667 at 266 FSB that would be a 4:5 divider, and again, as you scale up FSB the DRAM Frequency will scale up accordingly. So at 350 FSB your RAM would be running at DDR875 ((350*2)*5/4)).

If you had selected a DRAM Frequency of 800 at 266 FSB that would be a 2:3 divider, and again, as you scale up FSB the DRAM Frequency will scale up accordingly. So at 350 FSB your RAM would be running at DDR1050 ((350*2)*3/2)).

Does that clear up what you observed?

Some of that makes sense but how do you get the 2:3 divider? 800 divided by 266 is 3?

[Bloodshedder]

Remember DDR DRAM Frequency is FSB*2*divider. So 266*2 = 533 (well, actually 532 ...). If you leave the DRAM Frequency at 533 you are running a 1:1 divider (533(FSB266*2)/533 = 1 as does 1/1). FSB = 266, DRAM Frequency = 533, divider = 1:1.

If at FSB 266 you set the DRAM Frequency to 667 you are running a 4:5 divider (533(FSB266*2)/667 = .799 as does 4/5). FSB = 266, DRAM Frequency = 667, divider = 4:5.


If at FSB 266 you set the DRAM Frequency to 800 you are running a 2:3 divider (533(FSB266*2)/800 = .666 as does 2/3). FSB = 266, DRAM Frequency = 800, divider = 2:3.

Make more sense? By setting the DRAM Frequency for a given FSB, you are implicity defining the multiplier, be that 1:1. 4:5, 2:3 or 1:2.

[David9799]

Now i know why i can't understand...........your using fractions math never was my strong point.

All i really wanted to know was how to figure out what speed my ram is running at. I guess there is no software to tell you?

thanks for the help.

[theelectic]

It's easier if you think of it as a multiplier.

The motherboard takes your FSB speed, and multiplies it by a certain number to generate the memory speed.

For DDR2-400, you need 200MHz
For DDR2-533, you need 266MHz
For DDR2-667, you need 333MHz
For DDR2-800, you need 400MHz
etc.

If you're using a C2D then the lowest default FSB speed is 266MHz. If you set your BIOS to DDR2-533, then what does it have to multiply the FSB speed by to get 266? 1 (no change). So whatever you set your FSB at, the BIOS multiplies it by 1 to get your RAM speed (double it for the effective RAM speed).

With a 266 FSB and you want 400MHz RAM, so the BIOS multiplies the FSB by 1.5. So whatever you set your FSB at, it will multiply that by 1.5 to get the RAM speed. i.e. set your FSB to 400, it multiplies it by 1.5 to get 550, which is DDR2-1100.

CPU-z is a program which will tell you the actual speed of your RAM. But if you don't actually know how to set it properly in the BIOS, it will be useless.

BTW that RAM you linked to in your original post will probably not do much more than DDR2-850 (425 FSB @ DDR2-533 setting).

[David9799]

How do i set CPU-Z to tell me? I use it all the time already.

So if i am using 345x9 and the dram says 690mhz my ram is running at 1035Mhz?

If thats how you figure it i have had my ram run at 1200mhz!

400x9 dram says 800 = 1200mhz ram speed?


You say my ram wont go past 1275mhz? I would say your right if i am figuring it right.

[Lestat]

you really need to check out the overclockers guide man, seriously
this is basic basic overclocking stuff.

you dont "set cpuz" to do anything.
cpu-z will tell you exactly what your ram speed is. if you used it all the time you should know this. just take the speed it shows and multiply it by 2 for what your real speed is. dont ask about what about dividers and multi and all that crap. cpu-z give you your realtime ram speed. just take the number it shows and multiply it by 2.

im not going to add fuel to the fire by trying to explain things further.
you REALLLLYYYY need to understand your hardware before you go diving into this kind of stuff.
and you dont understand your hardware or overclocking.
your learning, for sure, but you skipped right over the basic stuff.

learn your bios and what the settings are, and learn cpuz (which takes all of about 2 seconds)

your on the right path but this stuff belongs in the newbie section or in the general hardware section.

this has nothing to do with intel persay, its basic overclocking.
i wish you luck man you'll get there soon enough.

[David9799]

I don't think its basic stuff. Where in CPU-Z does it say what the RAM is running at?

[David9799]

anyone?