Question about PC6400 DDR2 used with E6750/Q6600

[flashive]

I heard that it might cause the CPU to slow down because it has to wait for the RAM to finish its slower cycle. Is this true and if so how should I clock my RAM or my CPU to get the optimal performance out of my system?

Right now I'm putting together a system so I'd like to know what kind of RAM I should use in conjunction with my CPU.

 

[Rob Williams]

As a general rule, the RAM speed should be equal to the FSB speed. For a Q6600, that would be DDR2-1066, while for the E6750 (being a 1333FSB), then DDR3-1333 would be ideal. Obviously, not everyone is running out and paying the high DDR3 prices (and they shouldn't), so the bottleneck is not going to be a big one, if there is one at all.

In benchmarks, you might see small differences, but differences in real-world scenarios would likely be rare. This is something I am going to be looking further into within the next month or two.

Simply put though, don't worry about it. If, and that's a big if, there is any latency due to asynchronous settings, it's likely to be so minor, you will not notice it. For the sake of a 1:1 ratio though, I'd pick up DDR2-1066 RAM for the simple fact that it's so cheap.

 

[flashive]

So what about clocking my memory at 50% of the FSB, 533 instead of 1066, would that increase or decrease performance?

 

[Merlin]

I would just leave it as is.
You could severly change the performance of the whole machine.
Are you having some problems Now?
Or, are you just wanting everything to jive at the same FSB ?
Merline ( the coastermaker )

 

[flashive]

No as I said in my first post I am considering to buy a new system and RAM is the only thing I am not sure about at the moment.

I would just like to know how to setup my RAM and CPU so they work in the most efficient way.

 

[sbrehm72255]

DDR2 PC6400 runs at a native 400 FSB and the E6750 runs at a native 333FSB and the Q6600 runs at a native 266 FSB, thus a set of PC6400 still has plenty of roon left in it for over clocking.

Here's a example of my rig OC to 400x8 (3.2GHz) and the ram running at default PC6400 speed, you'll notice that it's running at a 1:1 ratio, which is exactly what you want. If you plan on OC'ing past a 400 FSB, you'll want either faster memory or OC what you have if it'll take it.

In this screenie the CPU and memory are both OC'd to a 450 FSB, thus running at a 1:1 setting, again this is what you're looking for.

 

[flashive]

Thank you sbrehm, that's what I wanted to know

Looks like a nice OC you had going there.

From what I've read it will require a good Q6600 in order to get to the 400FSB, in case the Q6600 doesn't make it to 400FSB would you recommend going down with the speed of the ram or is there no speed gain in that?