
AMD's Upcoming Ryzen 9 3900 Listed with 12 Zen 2 Cores at 65W - rbanffy
https://www.tomshardware.com/news/amd-ryzen-9-3900-specs-pro-cpu,40485.html
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pornel
According to [1] it appears that AMD rates CPU TDP for maximum load
(overestimating), while Intel rates them for load without turbo boost
(underestimating), so AMD's 65W is _really_ impressive.

[1]:
[https://www.youtube.com/watch?v=6u4ew6IT4Vo](https://www.youtube.com/watch?v=6u4ew6IT4Vo)

~~~
DiabloD3
You almost got it correct.

AMD rates it as non-turbo usage, ex: my $200 3600 is 65W TDP, has a package
limit of 88W, and is designed to reach 65W without turboing; if I manually set
the package limit to 65W, all cores will sit at the base clock of 3.6GHz
forever. 88W _hard_ package limit will be enforced under overclocking unless
overridden by user.

The comparison is the $250 9600k, same single-threaded performance, 3600 is
roughly 30% faster in multi-threaded; 95W TDP, _soft_ package limit of 150W,
and will exceed that under some situations under stock, and will absolutely
exceed it overclocked.

So, Intel, in this case, costs 25% more, has 30% less performance, has 46%
more TDP, and 70% more actual maximum usage... and to add insult to injury,
AMD's stock cooler is beefier than Intel's: I believe AMD's stock cooler can
sink 88W, I do not believe the Intel one can manage 150W+.

~~~
raihansaputra
Intel doesn't even ship coolers for higher TDP chips. I have a i7 7700 (65W
TDP) and the stock cooler and it's just too loud under high loads.

~~~
sq_
AMD's included coolers are one of my favorite little "bonus" things about
buying their chips.

As you said, Intel's stock coolers are known for being _loud_ , aren't
actually too great at dissipating heat, and aren't even included on higher TDP
chips. So you're almost automatically spending an extra $20+ over the chip
price on a decent cooler.

On the other hand, AMD ships solid coolers with (pretty much?) every chip.
I've run my R5 1600 with the stock cooler for two ish years without any real
heat or noise issues.

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pingyong
Are people still impressed by low TDP numbers? Everyone can manipulate that
number to anything you want by changing the base clock. Intel could sell the
9900K with a 25 W TDP by saying the base clock is 1200 MHz, AMD could do the
same. (I mean the 95 W TDP for the 9900K is already a meme.) It's just gonna
be exactly the same CPU as the 3900X, just a slightly worse binned version.

~~~
adrianN
If the performance is alright for my needs, why wouldn't I prefer a processor
with a lower TDP? I agree that it would be nice to have consumption numbers
for some standardized workload, but in the absence of that, TDP seems useful
to me.

~~~
pingyong
>If the performance is alright for my needs, why wouldn't I prefer a processor
with a lower TDP?

Because 1. a processor with a lower TDP doesn't necessarily actually use less
power, at least not if your cooler can dissipate much more than the TDP, which
it typically can.

And 2. because you can simply limit the clock speeds of any higher TDP CPU to
reach any TDP you want. If you want a 35 W 3900X or 9900K, just set the clocks
to whatever you need to reach 35 W max power usage, and you're done.

Of course the lower TDP parts are typically cheaper, so it makes more sense to
buy those. But _that 's_ their differentiating factor, the price, not the TDP.

~~~
Retric
TDP is very useful if you want a quiet PC without water cooling. Under
clocking may be required based on case airflow, but you want someone to be
making passive CPU coolers for your socket.

~~~
pingyong
Not sure what you're getting at, this is the same socket as all the other
Ryzen 3000 CPUs...

Not to mention that every slightly larger air cooler is a "passive cooler".
Just don't connect the fan. Or set a fan curve that disables the fan as long
as the CPU temperature is sub-62 C. Or 95 C, if you really don't want them to
turn on.

~~~
Retric
Yes, in this specific case it not a big deal, and they make some surprisingly
effective passive coolers today. However, I have run into this issue in the
past.

As to running a larger air cooler without a fan. That’s heavily dependent on
case airflow. High speed case fans really defeat the purpose of a passive
cooler.

~~~
pingyong
You don't really need any case airflow at all, it just depends on how much
performance you're willing to sacrifice. Case in point, you can run cinebench
on an 8700K without any cooler at all:
[https://www.youtube.com/watch?v=yA0oo12rbiM](https://www.youtube.com/watch?v=yA0oo12rbiM)

For something a bit more practical, if you're willing to get creative you can
passively cool CPUs while getting fairly high performance too:
[https://www.youtube.com/watch?v=N-z9PidYH4E](https://www.youtube.com/watch?v=N-z9PidYH4E)

Those are just NH-D15s, completely standard coolers with mounting brackets for
pretty much every consumer socket out there.

~~~
Retric
That second video uses fans see 5:40. Lots of closely spaced thin fins
actually produce less cooling without good airflow. There are real engineering
reasons passive coolers have significant air gaps between the plates.

PS: In terms of sacrificing performance, let’s agree to avoid the absurd. Or
as the guidelines put it: _Please respond to the strongest plausible
interpretation of what someone says, not a weaker one that 's easier to
criticize. Assume good faith._

~~~
pingyong
It uses fans, however IIRC the fan curves are such that they only kick in if
you render videos or do something else that 100% uses the CPU, and even then
they are fairly quiet. And again, if you simply limit the clock speeds and
voltages, you could disable the fans completely. (Or you could just disable
the fans completely in the first place and let the automatic regulation take
over.)

>Lots of closely spaced thin fins actually produce less cooling without good
airflow.

That is true, however Noctua coolers tend to have a fairly big gap between
fins, because they are designed for very low RPM use.

>In terms of sacrificing performance, let’s agree to avoid the absurd.

Not sure why you think it's absurd - the video just shows that there is no
real minimum amount of cooling required anymore, at least with Intel CPUs.
Obviously you're going to have to sacrifice _some_ performance if you go
passive only.

Although I'm not even sure anymore what we're even talking about. All consumer
CPUs use the same sockets. All these coolers are available for every modern
consumer or "pro-sumer" platform.

~~~
Retric
> All consumer CPUs use the same sockets.

Motherboard’s use a small set of different mounting brackets for CPU coolers.
But the physical CPU socket depends on several things including the physical
size of the chip and thus the amount of surface area you want in contact with
the the cooler.

In case you where unaware actually running a CPU at 100C will drastically
lower it’s lifespan. You encounter similar issue if there are significant
temperature differences across the chip. Which is why packaging includes a
metal plate over the CPU even though it reduces cooling. However, this is a
real tradeoff which means the contact area must be reasonably close to design
spec.

~~~
pingyong
Yes, bracket, not socket. What are we talking about again?

~~~
Retric
Selecting and then using passive CPU coolers. I am saying both the bracket and
socket are important when choosing a cooling.

For example, when introduced there was no aftermarket passive cooling
available for the AM4 socket.

Really of the 5 considerations “Does it fit the mounting bracket?” is probably
the least important. Fitting the motherboard and case are mandatory. Fitting
the socket and TDP have a little wiggle room. However, with mounting brackets
you can generally get something to work as long as you keep firm contact and
it does not wiggle around it’s fine.

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lpmay
No, the power consumed _is_ equal. The capacitance doesn't stop charging at
time tao as you imply, it continues to charge until it reaches the final
driving voltage, which is why integrating to infinity is a (very) much closer
approximation

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tracker1
The real question, will there be enough to meet demand... The only 3900X
availability currently, are price gouging.

Still eagerly waiting for the r9-3950X though.

~~~
sq_
If memory serves, things usually drop towards MSRP within a month or two for
AMD. Hopefully that'll happen with these.

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techntoke
Now imagine something like this with an integrated Navi GPU. That would be
killer.

