Hacker News Reader

Comment by ajross | Hacker News Reader

The snark in the thread is just out of control, guys. This is supposed to be a technical forum.

In fact the part in question is shown at 8 cores, 5 GHz turbo, with a 95W TDP (at $488), which shows somewhat better power efficiency than the equivalent Ryzen 7 3800X (8/4.5GHz/105W/$399).

Now, that price differential may or may not be worth the moderate performance and power advantages to you, or you might be more enthused by the bigger Ryzen 9 and Threadripper parts instead which compete in different segments. But this certainly isn't an uncompetetive part from Intel.

View on HN

Intel TDPs are the base clock, not the boost clock. AMDs are the boost clock.

A 9900K might specify a 95W TDP, but at 5GHz it will actually use almost 170W.

See https://www.anandtech.com/show/13400/intel-9th-gen-core-i9-9...

Cite for the AMD convention of TDP at a consistent boost? That's genuinely the first I've heard of it, and I'm almost certain that's wrong. TDPs have always been considered to be sustained values, which is exactly what "boost" is not.

The boost clocks generally are sustained values, at least if you have the cooling and power provision to make them so. Most good motherboards for Intel CPUs place no cap on boost duration although one is supported by the chipset. All of the benchmarks of high-end Intel parts like this are done with uncapped boost duration too. Yes, that does make Intel's TDP figures for this 5 GHz all-core boost part effectively meaningless.

AMD's current TDP figures are based the maximum thermal output in what they consider to be real-world applications with boost clocks enabled: https://www.techspot.com/article/1652-things-amd-needs-to-fi... (Their TDP used to be maximum thermal output full stop and the real-world figure used to be called ACP, but they changed it because comparing their TDP with Intel's made their CPUs look really hot.) They also have an actual guaranteed maximum which is higher than, but tied to, their quoted TDP figure. So whilst it's not actual TDP anymore it's still a lot more meaningful than Intel's numbers.

Hmm, you're right, I see anandtech data showing the 105W rated 3900x drawing a peak of ~120W. Still much closer to the rated TDP than Intel manages.

You can't really compare TDP and turbo clocks between AMD and Intel. [1]

The 9900k draws 168W at full load and is also specified for 95W TDP. This chip is likely going to use more. A 3900X draws 142W for comparison. (12 cores lower clocks 7nm)

[1] https://www.anandtech.com/show/14605/the-and-ryzen-3700x-390...

> In fact the part in question is shown at 8 cores, 5 GHz turbo, with a 95W TDP (at $488), which shows somewhat better power efficiency than the equivalent Ryzen 7 3800X (8/4.5GHz/105W/$399).

The 3900X 12C/24T uses less power under full load than the 9900K does: https://images.anandtech.com/graphs/graph14605/111362.png (142w vs. 168w)

Intel cannot touch AMD's power efficiency right now, at least not on the desktop market and up. AMD hasn't rolled out 7nm to the laptop space yet, so Intel keeps an advantage there.

The 9900K (and now 9900KS) are fast chips, but power-efficient they are very much not at all. Getting those clocks requires ramming power through the chip. Power efficiency is barely even a concern for this particular market area.

Reply on news.ycombinator.com