• Welcome to Overclockers Forums! Join us to reply in threads, receive reduced ads, and to customize your site experience!

Memory and CPU Vcore Relation

Overclockers is supported by our readers. When you click a link to make a purchase, we may earn a commission. Learn More.

dkizzy

Member
Joined
Nov 22, 2006
Location
PA
Just curious if anyone could explain this. On my AMD rig I was using 4GB of Supetalent DDR3 1333 memory. My CPU voltages were coming up at 1.27 in CPU-Z even though I had it manually set at 1.3375v. When I acquired some GSkill 8GB 1333 memory, the CPU-Z voltage went up to 1.32v which is much more accurate considering the vdroop. I was wondering why this was affected so much by just switching the memory. Any possible reasons would be enlightening! Thanks.
 
Your CPU voltage will vary based on the P-state/load/frequency that your CPU is running at. You would need to disable Cool and Quiet and C1E to see the default full load CPU voltage. The RAM should not have change the CPU voltage.

All memory has defined timings and voltage tags that are read on boot-up known as "SPD". The memory maker encodes the SPD based on the desired operating parameters. While there are industry standards for RAM, not all RAM conforms to these standards. Many mobos when set to "auto" will read the SPD and set the RAM to those specs. Some mobos do not. You may need to manually set the RAM parameters in BIOS for speed rated RAM that runs at higher frequencies and voltages than the industry standards.

http://support.amd.com/us/Processor_TechDocs/43375.pdf

http://en.wikipedia.org/wiki/Serial_presence_detect
 
Last edited:
Thanks for the info. I did leave it set to auto and I just found the experience odd. Maybe the SPD was the culprit to the cause. All I know is the GSkill set on auto was much more accurate. I have no hate for SuperTalent memory. Every purchase of it has been solid with the exception of that odd vcore correlation. I did have cool n quiet enabled during that testing, so sometime I will pop it back in with the settings disabled and see what happens!
 
Back