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papoulka
Adept I

What is a normal idle power for 3900X?

I mean "CPU Package Power" as seen in HWInfo, on a quiet Windows 10 desktop with overall CPU average usage at about 2% or less.

I'm seeing ~32W which seems high and also doesn't appear to correspond to the related voltages and currents.  My BIOS has XMP and PBO enabled, and LLC = 8 (off); otherwise stock settings.  This isn't a problem but I'm curious.  

Would appreciate a few data points from other 3900X owners, thanks.

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6 Replies

My old Phenom II X4 965 BE would go down to 1W at idle. Ryzen do not seem to be as low but the TDP is less than 1/2 the the old CPU so the net savings will be positive longer term.

More power is saved with standby

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It may seem high, but with all the things inside a Ryzen CPU, chiefly the I/O chip but also the Infinity Fabric, L3 cache, things like that which would be defined under the "un-core", as opposed to the CPU cores, L1 and L2 cache, things like that are defined under "core". While the cores themselves throttle back quite well, the Un-core parts of the chip really can't, and that leads to the seemingly high package power.

Anandtech did a great power test with their 3900X review, showing how even under a very lightly threaded load the unused cores will throttle back greatly to even hardly measurable consumption, but the un-core parts have a power consumption which exceeds the cores.

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There are a lot of things in the modern Ryzen compared to the old Phenom. My CPU has TPM logic so it is possible to use bitlocker etc . No need for an expensive card to plug onto the board. All of the cores are dynamic which complicates the analys more.

My PSU is 80 plus platinum so it is relatively efficient which has very measurable gains.

A while ago I posted a video of somebody with a R9 3950X and see how much power it would use overclocked and pushed hard, The CPU got past double the TDP at one point and windows still loaded.

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papoulka
Adept I

Thank you, black_zion.  I had hoped for at least one direct answer to my simple question relating specifically to the 3900X at idle, and you did a great job in providing it.  I understand now that the un-core is probably responsible. Though it still would be interesting to have a 3900X owner say what they see for this value in HWInfo.

Hardcoregames - You're probably trying to help, but posting info unrelated to the OP question complicates the picture, discourages others from reading through or answering it themselves, and generally muddies the water.

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I wish I had a 3900X, but sadly I haven't hit the lottery yet so I'm stuck with my 1800X

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black_zion wrote:

I wish I had a 3900X, but sadly I haven't hit the lottery yet so I'm stuck with my 1800X

neither have I

this is why I have an R5 3600 .....

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