A question regarding CPU overclocking and it's relation to RAM.

[Snozaz]

Hello

I do not know much about overclocking enough to do it manually, so I went with the Asus auto overclock feature. It gave me a clock speed of about 4.23Ghz although I noticed it lowered my ram speed to 1347mhz. Does anyone know why it would do this?

My RAM is rated for 1600 and supports XMP, would it be safe to manually raise the RAM speeds to 1600 after using the auto overclock? (in the drop-down menu the number is slightly higher, 1640-something)

If I enable XMP it overrides the auto tune settings and sets the CPU at 4.1, that's how I have it running right now.

I'm hoping someone can shed some light.
Thanks!

 

[hunter315]

What CPU and RAM do you have?

If it has to OC the CPU by increasing the base clock it will reduce the RAM:bus ratio to avoid cranking the RAM clocks too high and making the system unstable.

 

[Snozaz]

What CPU and RAM do you have?

If it has to OC the CPU by increasing the base clock it will reduce the RAM:bus ratio to avoid cranking the RAM clocks too high and making the system unstable.

Thanks for responding.

I have an 3570k cooled by an corsair h100 with 2 x 8 corsair vengeance blue.

 

[hunter315]

Alright, so in order to get it to 4.23 it definitely had to adjust the base clock. For recent intel chips that is 100 MHz, in order to get to 4.23 GHz it took you up to a 42x multiplier and bumped the base clock up just a little bit to 100.7 MHz, and this would have increased your memory clocks up past the 1600 MHz it was set at, but it doesn't know if this is stable so it bumped you down. If you had spent time OCing the memory prior to the CPU and found the maximum settings for the memory and then it boosted the base clock a tiny bit it would be unstable and the point of the auto OCing utilities is to be a bit conservative and get you some OC without making the system unstable.

When you enabled XMP, it set the base clock back to 100 MHz so it could use the normal memory multiplier, and then it dropped the CPU multiplier by 1 for some reason(idk what)

 

[Snozaz]

Alright, so in order to get it to 4.23 it definitely had to adjust the base clock. For recent intel chips that is 100 MHz, in order to get to 4.23 GHz it took you up to a 42x multiplier and bumped the base clock up just a little bit to 100.7 MHz, and this would have increased your memory clocks up past the 1600 MHz it was set at, but it doesn't know if this is stable so it bumped you down. If you had spent time OCing the memory prior to the CPU and found the maximum settings for the memory and then it boosted the base clock a tiny bit it would be unstable and the point of the auto OCing utilities is to be a bit conservative and get you some OC without making the system unstable.

When you enabled XMP, it set the base clock back to 100 MHz so it could use the normal memory multiplier, and then it dropped the CPU multiplier by 1 for some reason(idk what)

That makes sense. Thanks!

When I enable XMP from bios defaults it brings the CPU to 4.1 and ram to 1600. It's a profile I have to switch to, so it will undo what the auto OC set.

I have tried only adjusting the ram speed after the auto OC finishes, and it seems to work fine. Would would you recommend using to test for stability?