cpu overclocked itself?

[farhanorakzai]

i have my ram set to xmp 2800mhz and cpu multiplier on auto. cpu-z and aida64 says my cpu is at 4.2 ghz. how does that happen? 

[Aniallation]

i have my ram set to xmp 2800mhz and cpu multiplier on auto. cpu-z and aida64 says my cpu is at 4.2 ghz. how does that happen? 

Turbo Boost?

[Enderman]

pretty sure your XMP changed the base clock...

[dragoon20005]

FSB or BCLK will affect RAM speed and vice versa

 

so if you OC your RAM,

 

your FSB will be affected too

 

so you get free MHz just by applying your XMP profile

[farhanorakzai]

Turbo Boost?

it should turbo boost to 3.5 ghz 

[Blackie Sheen]

Try different xmp settings see if that changes anything. Also, verify your BLCK. If its not at 100 put it back there

[harrynowl]

X99 sets the base to 125 from 100 with some RAM frequencies I believe. @runit3 may know more I know he has lots of fun with DDR4 RAM on X99 :wacko:

[runit3]

i have my ram set to xmp 2800mhz and cpu multiplier on auto. cpu-z and aida64 says my cpu is at 4.2 ghz. how does that happen? 

If you could link your DDR4 kit that would be helpful. Some kits over 2133 require the BCLK to be adjusted to 125 (from 100), this would explain the corresponding change with your CPU multiplier. You can either reduce the CPU multiplier, or leave it where it is and adjust your voltage.

 

[farhanorakzai]

If you could link your DDR4 kit that would be helpful. Some kits over 2133 require the BCLK to be adjusted to 125 (from 100), this would explain the corresponding change with your CPU multiplier. You can either reduce the CPU multiplier, or leave it where it is and adjust your voltage.

2 16 gb kits of dominator platinum ddr4 2800mhz

[runit3]

2 16 gb kits of dominator platinum ddr4 2800mhz

 

"Very similarly to DDR3, but with some caveats. For starters, Haswell-E tops out at a 2666MHz memory strap, which is very low for what DDR4 can do. Since XMP specifies speeds in excess of 2666MHz, your motherboard BIOS has to compensate somehow. Typically, when XMP tells the motherboard to use a higher memory speed than 2666MHz, the motherboard BIOS will bump the BClk strap from 100MHz to 125MHz. That’s normal, but that change will also increase the clock speed of the CPU itself; a well-designed BIOS will compensate and bring the CPU clock speed in line."

 

From the Corsair tech support page: http://www.corsair.com/se-fi/dominator-platinum-series-16gb-4-x-4gb-ddr4-dram-2800mhz-c16-memory-kit-cmd16gx4m4a2800c16

 

BCLK has been bumped to 125. You can either leave the OC on the CPU in place, and give it a corresponding bump in voltage for stability, or simply reduce the CPU multiplier to get it back closer to stock. Your choice. If you have adequate cooling, I would keep on OCing :lol: