Memory Speeds vs. Proc FSB~

[[interloper]]

Ok ok, So I am positive its asked a million times in this forum...but since I will get a better understanding if I ask rather than troll...I am gunna~ heh

So I am planning on getting the ASUS P5K-VM (rates a 1333/1066fsb)...the processor is gonna be a e6700 (as of now waiting for price drops to see if I wanna go faster, but the FSB is rated at 1066)...The memory Crucial Ballistix DDR2 1066 (PC2 8500)...

Now I look at all this and I have been reading quite a few posts...It seems to me I get it out of the box and plug everything up (no BIOS adjustments or OCing) and it everything should run at the rated speed?

Or am I just living in a fantasy world and am in desperate need of it being shattered so I can see whats really going on heh...

(I have seen in some other threads where people are having to mess with their FSB settings and stuff to have their memory run at the rated speed...I guess it wont be a problem if I have to manually put into my BIOS what my proc and memory are rated for but yea, I am trying to stay away from heat/OCing for now till I get a good idea what I will be dealing with in my lil case )

 

[BillParrish]

Or am I just living in a fantasy world and am in desperate need of it being shattered so I can see whats really going on heh...

Yes

Ok here is what you need to remember:

Current Intel CPUs (since the P4) are quad pumped, that means for each "real" FSB clock tick they can perform 4 actions. Intel rates the CPU buss speed already taking into account this quad rate to make their CPUs sound more impressive. The "real" FSB is the Intel advertised cpu buss speed divided by 4.
So for an Intel 1066 buss cpu the "real" FSB is 1066/4 = 266MHz
The CPU speed is the CPU multiplier x the "real" FSB.
DDR2 memory runs at 2 x the real FSB, hench the name double data rate.

------ if you remember the above you are 99% where you want to be. -------

So when you plug in your 1066 buss speed CPU the "real" FSB will get automatically set to 266MHZ

Most motherboards will set the memory speed to the default DDR FSB x 2 rate and your memory will run at 533MHz. Not where you want to be!

You dream now lies in little pieces on the floor. All that money for expensive ram and its barely being used at half its rated speed.

POOF! (Fairy Godmother appears waving magic wand and speaks the words...)

"Fear not brave newbie, there is a potion to restore your dream of high speed ram bandwidth. This magic is called "memory mulitpliers"" !

Most if not all enthusiast motherboard have what are called memory mulitpliers. Default memory speed is the 2 X FSB as mentioned above however settings in the bios let you change this ratio. One issue is that remembering the above technical details about the "real" FSB and doing the 5th grade math is considered too difficult for the average computer user. So Asus makes it easy. However you will have to find the keyboard key that will activate the BIOS menu when the computer starts up to enable the magic. Once that is done and you are at the main bios screen.

Highlight and select: Advanced Menu (from the tabs at the top)
In Advanced Menu select : Jumperfree Configuration
Find: DRAM Frequency [Auto]
Change DRAM Frequency to: DRAM Frequency [DDR2 1066MHz]
Back out of the menus, save and exit.

This will enable the magic mulitpliers and you will compute happily ever after.

(Fairy Godmother departs, having cleaned out your stash and your best bottle of Scotch has disappeared. )



Note to self: 40 years ago "Fairy Godmother" and "magic wand" were terms of comfort and Disney like wonder, now they are just creepy, knock it off.

 

[[interloper]]

I guess I owe you a thank you, but now I am going to go wonder around lost for a while.

hah