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Safe CPU Core Current Limit

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Animalm4st3r View Drop Down
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    Posted: 03 Feb 2018 at 7:35pm
Because the actual TDP is 95Watts when Boosting and even more when overclocking thus you need more amps
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Eigua View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Eigua Quote  Post ReplyReply Direct Link To This Post Posted: 03 Feb 2018 at 5:19pm
I downloaded Intel's XTU to help determine what was happening with the current limit.

I was able to see the default settings set by the motherboard for the CPU Core Current Limit when current throttling kicked in. I was pretty surprised by what I saw.

Default current throttle limit: 255.500A

After some testing, I was able to determine that during stress testing using the default settings, the CPU is pulling 147A -- 14A over the published ICCMax value. I determined this by progressively changing the current throttle limit until it stopped throttling.

So now the question is, if the ICCMax is 133A, why is the chip pulling 147A on default settings?



Edited by Eigua - 03 Feb 2018 at 5:19pm
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Eigua Quote  Post ReplyReply Direct Link To This Post Posted: 03 Feb 2018 at 1:23pm
I know that the BIOS setting OC Tweaker -> CPU Configuration -> CPU Core Current Limit allows you to set a maximum current for the CPU. What I don't know is, what is a safe maximum value for this for an Intel Core i7-8700? I can't find this information in Intel's datasheets.

I know this value is an upper limit, but I'm trying to tune for heat reduction. Setting this value to something like 95 causes the frequency to cap out around 3.3GHz. Only at 145 or higher does it reach 4.3GHz turbo speeds when I'm undervolting. I have no idea if this is safe or not.

Motherboard: ASRock Fatal1ty Z370 Gaming-ITX/ac
CPU: Intel Core i7-8700

Edit:
I ended up finding what I was looking for in the datasheet, page 110:
ICCMAX, 65W Hexa-core GT2 = 133A


Edited by Eigua - 03 Feb 2018 at 3:25pm
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