Question How to define TDP?

[Wing901]

The TDP of Ryzen 9 7950x3d is 120W. Does it mean it only draws 120W from the power supply or it only consumes 120W?

 

[zinkles]

TDP is the max amount of heat generated by a component under max load (typically to decide on a cooler that's suitable for it). It's often confused by how much power a component draws, but while that may hover around the TDP range, its not how much the component takes in, rather gives out as heat.

 

[Wing901]

Do you mean a CPU/GPU probably consumes more watts than its TDP?

 

[Eximo]

It is not the Maximum amount of heat. It is the rated heat that you are expected to dissipate to maintain baseclock performance. Boost profiles and other power limit modifiers like PBO will change the amount of power required and the amount of heat you need to dissipate.

CPUs will often exceed the TDP supplied by the manufacturer for significant amounts of time as long as temperatures allow. GPUs do this as well, but for only brief instants. Some older power supplies will trip / trigger a restart if they can't handle sudden power spikes.

In terms of power supply, yes, the power input required roughly equals the power output, though that depends on the efficiency of your power supply, and in the case of CPUs, the efficiency of your motherboard VRMs. Always best to over spec a powersupply by around 100W over the worst case, or more as total power requirements rise.

There is no real standard for TDP, so best to go along with reviews when picking CPU coolers.

You may also see the term TBP (Total Board Power) Which is often what GPUs are covered under.

 

[Wing901]

Thanks. How do I know the exact watts a CPU/GPU draws?

 

[TerryLaze]

It's neither of those two things, not for AMD.
Their calculation of TDP is complete nonsense, that of intel is a little bit better but also not very true.
https://gamersnexus.net/guides/3525-amd-ryzen-tdp-explained-deep-dive-cooler-manufacturer-opinions

The TDP of Ryzen 9 7950x3d is 120W. Does it mean it only draws 120W from the power supply or it only consumes 120W?

The 7950x is rated for 120W so it can use up to 162W ,that's the PPT number.
Also the amount of power the CPU consumes is the same amount of power that it draws from the PSU.
The PSU could have bad efficiency and draw more power from the wall than the CPU consumes, that's a different thing.

Ryzen 7950X3D review: An expensive but incredibly efficient 16-core CPU

AMD’s second run at a 3D V-Cache CPU is easier to recommend than the first.

arstechnica.com

	65 W TDP (AM5)	105 W TDP (AM5)	120 W TDP (AM5)	170 W TDP (AM5)
PPT (W)	88	142	162	230
TDC (A)	75	110	120	160
EDC (A)	150	170	180	225

 

[USAFRet]

Thanks. How do I know the exact watts a CPU/GPU draws?

The CPU/GPU does not work in isolation.

You measure the power draw of the whole system.


What actual information are you looking for?

 

[Wing901]

I just wanted to know what power supply I should use..

 

[Wing901]

The 7950x is rated for 120W so it can use up to 162W ,that's the PPT number.
Also the amount of power the CPU consumes is the same amount of power that it draws from the PSU.
The PSU could have bad efficiency and draw more power from the wall than the CPU consumes, that's a different thing.

What about the intel CPU? The TDP of i7 14700K is 125W to 253W. How many watts does it really consume?

 

[USAFRet]

I just wanted to know what power supply I should use..

Right.
And that is when you MUST take into account the whole system.

"What power supply" is found by discussion, with people that know.
Like a lot of people here.

 

[Eximo]

What about the intel CPU? The TDP of i7 14700K is 125W to 253W. How many watts does it really consume?

Depends how you set it up, but it can reach 253W consumption easily with good enough cooling. And you can overclock it beyond that, 300+ watts is not impossible with water cooling.

It won't do that all the time, just when you load up all the cores. Same with AMD, it would take an all core load to see the high power numbers.

 

[TerryLaze]

Depends how you set it up, but it can reach 253W consumption easily with good enough cooling.

Where good enough cooling could be a $20 ag400 which does 247W average sustained on an 13900k.
https://www.tomshardware.com/reviews/amazon-basics-cpu-cooler-review/2

 

[DSzymborski]

Do you have a specific PC you're buying a PSU for that you need assistance with? If that's the case, it might be a lot quicker to just ask the question directly rather than ask an open-ended theoretical query on how one *would* answer such a question.

 

[Wing901]

Do you have a specific PC you're buying a PSU for that you need assistance with? If that's the case, it might be a lot quicker to just ask the question directly rather than ask an open-ended theoretical query on how one *would* answer such a question.

i7 14700k, 32G DDR5, 980 Pro SSD, WD Blue 4G harddisk, RTX 4070 ti super or 4080 super(going to buy).