Enabling XMP is reverting my CPU clock back to stock...seeking some help

As the title suggest, whenever I turn on XMP my clock speed reverts back to stock.

So I bought a bundle back in 2011 - it's a Gigabyte P55 MOBO with dual channel ram slots.

I've always run the bundled 4GB that came with the machine. Last week I bought these from OCUK https://www.overclockers.co.uk/cors...l-channel-kit-cmx8gx3m2a1600c9-my-290-cs.html

I wanted to double the ram up to 8GB. The sticks I purchased above are exactly the same sticks already in the machine. I popped these into the two extra slots - everything seems fine and it's showing the jump to 8GB. But CPU-z isn't calculating a speed of 1600mhz.

A quick google suggested turning on XMP in the BIOS.

I did this - now my CPU speed has dropped from 4 to 2.8 GHz. I reloaded the default CMOS profile and now its reverted back up to 4, but I have to leave XMP off.

Any idea's why this might be happening?
Is there a way I can get my new ram up to the 1600 it states on the product without using XMP?

I should also mention my OC knowledge is quite lackluster!

Any help on this is really appreciated - thanks

What cpu have you got?

In the bios change your cpu settings from auto to manual and set everything to their stock levels and enable XMP for your RAM

Download a program like Cpuz and get your timings, then put them in bios with correct voltage.

Thank you for the replies.

The OC profile I'm using is the original one set by OCUK when I bought the bundle back in 2011 - I've never changed any of the settings before due to a lack of knowledge in that department.

These captures are taken from CPU-Z showing the OCUK profile without any alterations.





So if I turn on XMP - I gain the faster RAM speed, but lose the CPU speed as it drops back down to stock 2.8Ghz.

I'm not sure what I need to change in the BIOS config - can you shed any light on what I'd need to do exactly?

Again - thanks for your help with this.

EDIT: I've just realised I need to double the DRAM frequency since it's dual channel, which gives me about 1527Mhz already - not as bad as I thought it was! Do you think I'd have a noticeable difference if I increased anything to get it to 1600?

Thanks

All your settings are correct

If you look under Memory tab in cpu-z, it shows FSB : DRAM 2:8 (1:4)
This is your bus speed x 4
so 191 x 4 = 764

To get your ram up to 800 you would need to set your CPU clock ratio to 20 and BCLK frequency to 200

This will clock your cpu at 4Ghz and your ram will be at 800

Leave XMP disabled and check everything in CPU-Z

I find it strange that it's been clocked like that. 20x200 makes much more sense than 190x21 and keeps the ram at full speed

liamd89 said:

All your settings are correct

If you look under Memory tab in cpu-z, it shows FSB : DRAM 2:8 (1:4)
This is your bus speed x 4
so 191 x 4 = 764

To get your ram up to 800 you would need to set your CPU clock ratio to 20 and BCLK frequency to 200

This will clock your cpu at 4Ghz and your ram will be at 800

Leave XMP disabled and check everything in CPU-Z

I find it strange that it's been clocked like that. 20x200 makes much more sense than 190x21 and keeps the ram at full speed

Click to expand...

Thanks for the feedback Liam - truthfully I've no idea why the CPU is clocked this way. I've always just used the profile that OC set when I purchased the bundle off them.

I won't get to my rig until Friday now, but I'll give your suggestions a shot and report back the findings.

Thanks again for the info

Just a quick update on this.

Clock speed is back up to 4Ghz and RAM is at 1600.

Thanks again for your help - your suggested settings worked