News Intel Core i9-13900KS Review: The World's First 6 GHz 320W CPU

[thestryker]

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It hurts thermal efficiency, but I doubt it has much impact on perf/W. The main effect is that, to avoid thermal throttling, you need a beefier cooling solution than you otherwise might (for a given power limit).

From the handful of examples I've seen it's somewhere around 5-10% on the perf/W side of things, so it's not significant, but it is a measurable amount.

Once you have sufficient cooling it doesn't matter how good your cooling solution is due to the poor heat transfer. Mike at Hardware Canucks even noted this in his video going over coolers for the beginning of this year as the reason they're not using AMD for testing.

 

[bit_user]

Once you have sufficient cooling it doesn't matter how good your cooling solution is due to the poor heat transfer.

Yeah, if I had a Ryzen 7000 and really wanted to get the most out of it, I'd be very tempted to de-lid.

But, again, just because you hit the thermal ceiling doesn't mean you're leaving a lot of performance on the table. If you refer back to that graph, you could limit a 7950X at 125 W and still get 96% of the max performance. In that case, you don't need to go crazy with cooling, either.

 

[Deleted member 431422]

....
If you aren't doing stuff that needs this performance why the heck do you buy a 12900K/KS or similar CPUs in the first place?!?
If you do, AMD provides better performance/watt.

It's why I own AMD CPU. It can stay within it's TDP of 65W (not counting PBO, I doubt it's being used often with how I use the system). ZEN is very efficient.

 

[KyaraM]

It's why I own AMD CPU. It can stay within it's TDP of 65W (not counting PBO, I doubt it's being used often with how I use the system). ZEN is very efficient.

I trimmed down my 12700K quite a bit, too, not as if you can't do that with Intel. Gaming doesn't get over 70W or so even in demanding titles and sits at maybe 40W average, and Cinebench gives me normal results (22700-23700 depending on what mainboard settings I use; no auto-OC, or auto-OC on) for 40W-50W less than Intel's specs. AMD also has two power limits, and high-end AMD chips go well past 65W, too. If your chip has 65W, it's most likely a lower-end one. My 12100 in the other system uses 57W average and 58W tops, 12-34W in games, and still eats many more expensive older chips with higher power draw for breakfast; it's rated for 60/89W. I was talking about the high-end, though. Where neither Intel nor AMD is very efficient without tuning these days and CPUs easily eat 120W and more.

 

[TerryLaze]

AMD also has two power limits, and high-end AMD chips go well past 65W, too.

Not just high-end ones, ppt for 65W tdp is set at 88W and that's what any ryzen 65W TDP cpu reaches under heavy load.

Package Power Tracking (“PPT”): The PPT threshold is the allowed socket power consumption permitted across the voltage rails supplying the socket. Applications with high thread counts, and/or “heavy” threads, can encounter PPT limits that can be alleviated with a raised PPT limit.

1. Default for Socket AM4 is at least 142W on motherboards rated for 105W TDP processors.
2. Default for Socket AM4 is at least 88W on motherboards rated for 65W TDP processors.

 

[KyaraM]

Not just high-end ones, ppt for 65W tdp is set at 88W and that's what any ryzen 65W TDP cpu reaches under heavy load.

Yeah, I know. Was talking strictly about TDP there, which, for let's say an Ro 5950X, is 105W iirc.

 

[Brian D Smith]

This is weird reasoning. So, you're saying that if AMD had set lower power limits to make their CPUs stay in the efficiency sweet spot, you'd be fine with getting one? But, because they allow the CPU to boost higher by default, you consider it a "waste" if you have to change the settings to restrict it yourself?

I think a much more rational basis on which to decide is to look at how performance scales as a function of power limit. We see that most of the performance of the 7950X can be extracted by 125 W, whereas you have to keep juicing the i9-13900K to reach the knee in its perf/W curve.

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Source: https://www.anandtech.com/show/17641/lighter-touch-cpu-power-scaling-13900k-7950x/2​

So, you're really not leaving much on the table, if you go with like a 7950X and restrict it to 125 W. Plus, you don't need to spend the money on a cooling solution capable of much more than that. If you opt for a model with fewer cores, the efficiency curve will bend sooner. So, the equivalent limit for the 7900X might be just 105 W.

In the notes the author indicated he did not indicate the CPU socket power draw. "I did use PPT for AMD, but why they are going above that threshold is something I need to test on more boards, which I need some time for."