The best RAM speed for the P5Q Pro

[golgii]

Why does everyone seem to be buying DDR2 800 (PC2 6400) RAM for the P5Q Pro motherboard? The MB supports 1,600, 1,333, 1,066 and 800MHz memory modules. Am I missing something?

 

[knotknut]

You are missing something.

You need to know what processor you are using.

Edit: The motherboard supports FSB 1600/1333MHz . That is not RAM speed

 

[golgii]

I would like to put together a pc with the following components:

* Vista Ultimate 64 bit ed

* Asus - P5Q Pro
- FSB: 1600/1333 MHz
- Mem: 4 x 240, DDR2 1200, 8Gb

* E8400 Wolfdale - 45nm
- 3.0 GHz - 6MB L2 Cache

* Just need to identify the type of RAM.
- I think the max for the MB is DDR2 1200 (PC2 9600).
- However, most people seem to be buying DDR2 800.

Can anyone recommend what type of RAM I need? If at all possible I would like to oc the FSB up a bit to get a faster CPU speed around 3.5 GHz.

 

[knotknut]

The E8400 has a multiplier of 9.
9 x 333= 2997 or 3.0GHz With DDR Ram at 1:1 it would be 2 x FSB(333)=667. That would be the speed of the ram. DDR2 800 would be more than enough.
You want 3.5GHz out of your CPU. 9 x 400=3600MHz or 3.6GHz
The Ram DDR2 ( double data rate) 2 X FSD(400)=800 So here the ideal Ram will be DDR2 800. Any thing more than that would be a waste of your $.

 

[outlw6669]

Why does everyone seem to be buying DDR2 800 (PC2 6400) RAM for the P5Q Pro motherboard? The MB supports 1,600, 1,333, 1,066 and 800MHz memory modules. Am I missing something?

CL4 DDR2 800 has the exact same access time as CL5 DDR2 1066, CL7 DDR3 1333 and CL8 DDR3 1600.
Unless you are running a high end server, the extra bandwidth will do nothing for you.
As DDR2 800 is cheap and can overclock nicely, there is really no need to waste the cash.

http://www.thetechrepository.com/showthread.php?t=160
http://www.thetechrepository.com/showthread.php?t=195

 

[golgii]

Well that solves that question. Thanks for the replies!

 

[roadrunner197069]

P5Q says 1200 but i can tell you from experience it dont run OC well with 1200, especially with 8g. 1200 ram equires to much voltage and this board dont like it. And with 8g you'll have to bump voltage even more.

800 ram is the sweet spot.

400x9
450x9
500x9 with water cooling.

 

[ausch30]

Why does everyone seem to be buying DDR2 800 (PC2 6400) RAM for the P5Q Pro motherboard? The MB supports 1,600, 1,333, 1,066 and 800MHz memory modules. Am I missing something?

You are missing something, there is no such thing as DDR2 1000, 1066, 1333 and so on. The only actual DDR2 speeds are 400, 533, 667 and 800.

 

[hopelessliar]

You are missing something, there is no such thing as DDR2 1000, 1066, 1333 and so on. The only actual DDR2 speeds are 400, 533, 667 and 800.

Well that puts this into something of an existential quandary:

http://www.ebuyer.com/product/119223

 

[ausch30]

You are missing something, there is no such thing as DDR2 1000, 1066, 1333 and so on. The only actual DDR2 speeds are 400, 533, 667 and 800.

Well that puts this into something of an existential quandary:

http://www.ebuyer.com/product/119223

That is DDR2 800, buy it and you will see. It will be recognized by the motherboard as 800 and CPUZ will show 800. It is guaranteed by the manufacturer to overclock to 1066 but make no mistake it is DDR2 800.

 

[outlw6669]

Sorry ausch30, you would have been correct for the longest time but JEDC has approvied DDR2 1066.
Here is their specification sheet for it.
It must have been approved fairly recently as the spec document is dated November '07.

 

[ausch30]

Sorry ausch30, you would have been correct for the longest time but JEDC has approvied DDR2 1066.
Here is their specification sheet for it.
It must have been approved fairly recently as the spec document is dated November '07.

I stand corrected. Most is still 800 and anything sold above 1.8v +/- .1v isn't true 1066 but I do see that they've finally ratified the standard.