i7 overclock bundle: 12GB of RAM limits overclock

[dave_ryman]

Hi,
When I look at the customisation page for the overclocked i7 bundles, it states that selecting 12GB of memory may limit the overclocking. Three questions:

Why? Is there a simple(ish) reason why this is the case?

To what extent? Is it going to result in a little reduction (say, 3.8GHz instead of 4GHz), or make the overclock totally impossible?

If I win the lottery later on and decide to install even more memory (I understand that these motherboards can take upto 24GB), how will this affect things?

Regards
Dave

[PeteG@Scan]

Hi Dave,

Matched memory is rated with certain timings, at a certain voltage at a set speed. If you double the amount of memory we then need to tweak up these settings to obtain the same results. In most cases this means upping the voltages but most memory firms advise slackening the timings off as well.

These days the memory controller itself is located on the cpu and when overclocking it's important to balance the voltages between the components as these days systems can fail testing when the voltages are too high as well as too low. When working with all memory banks populated the controller has to work that much harder and more voltage is required which means more heat generated. We put as much voltage through as we feel is safe to do so, but sometimes we need to back it off to maintain a stable overclock and this is where we have to drop the speed to achive the working solution.

How much of a reduction is required we can't tell until the componants are on the desk i'm afraid. I'd expect 3.6 - 3.8 rather than 4.0 - 4.2 (for instance).

This is more a slot thing rather than a memory size thing. If you have 12GB to start with on 3 slots I'd expect the full overclock and if you have it on 6 sticks i'd expect less.

In the future if you want to add 24 then it may need downclocking slighty if you started out with 3 sticks or if you replace the lot after starting with 6 sticks i'd expect no change in overclock.

Pete.

[dave_ryman]

So it's the onboard memory controller generating heat - that makes sense, thanks very much.

I'm thinking that 6GB at full overclocked speed might be a better system than 12 or 24GB running at a slower speed.

Dave

[PeteG@Scan]

Would all depend on what your doing with it. To be honest unless your doing audio or video editing it's still pretty hard to max out 6GB let alone more than that, so the full overclock may make more sense.