Hacker News Reader

Comment by uni_rule | Hacker News Reader

It seems that if you don't opt for AMD on AMD this new generation of PCs will be absolute toaster ovens.

AMD is also in the process of being a toaster oven. The new Ryzen 9 7950x will use considerably higher power (105W -> 170W) for a smaller die area, which is making people worry about air-powered cooling being not enough (previously a Noctua D15 was enough to cool a 5950x). And I really don't want high-end CPUs to require water cooling since it's more unreliable and requires more maintenance.

those are base-clock TDPs not the boost TDPs (which AMD calls a PPT) too... it's 170W base/230W boost power, and those chips are allowed to boost for an unlimited duration (which of course has pluses and minuses).

> 7950x will use considerably higher power (105W -> 170W)

The 5950X uses 180W at full load. Some measure as high as 230W. The 105W figure reported as "TDP" was a mistake.

Not sure why the specs were a big lie but this is well documented online.

> air-powered cooling being not enough

If you want to turbo to 4.1GHz or better on all cores on the 5950X, you have to spend about $60 on a cooler - water or air. The AIOs perform well. A big AIO will give you 4.5GHz. No turbo air cooling - 3.4GHz - is a waste of money.

I can definitely confirm this, I tried to air cool my 5950X without much luck. Enabling PBO I've seen it go over 200W, which a 240mm rad handles very well.

Huh. Interesting. I put a noctua heatsink (dual fan) on mine but I am guessing this is why my overclocking curves weren't that great. Any chance you have the rough before/after numbers and how much did you splurge for the water cooling?

There's a small silver lining in that you can set hard power limits in the bios and amd claims it's still ~15% faster when limited to 105w. It would be nice if they just left it at that but it makes them look worse in benchmarks against Intel since most people won't check the power consumption.

keep in mind that is not idle power consumption. If you are setting a limit like that it's because of heating or power constraints (battery? PSU?)

Since noctua nh d15 air cooling has been on par or surpassing any aio and even all but the high end custom loops. https://www.youtube.com/watch?v=PeQX1uhb0iQ

Not really. The NH D15 is an impressive cooler, but it falls behind 280 AIOs. Even ones cheaper than itself.

https://www.gamersnexus.net/hwreviews/3571-arctic-liquid-fre...

Yeah I admit that there are cheaper water coolers than Noctua that perform better. But the main issue I have is with water cooling itself (can burst or leak if unlucky or with poor maintenance, has a more limited life span, etc...)

Intel power scaling works very well. My 12th-gen 12700K says its is drawing 660mW at the moment, and its complete silence is consistent with that estimate. If there's some power level that you prefer, you can just enter it in the BIOS and leave it that way.

Personally, I do not pretend that CPUs are light bulbs. If my CPU could draw 1000W for 10ms and that made short tasks like web page rendering twice as fast, that's a trade I would happily take. The short-term power consumption of CPUs is pure benefit to the user, and the rarer sustained tasks that run all the cores flat out for more than 1 second are always going to level off at about 125W because of the long-term cooling situation.

Intel CPUs have better idle power consumption that even the latest Ryzen CPUs. It caught me off guard when I switched from Intel to AMD and the idle draw of my PC went up by a significant amount.

Given that our computers spend more time idle than at 100% peak load, my AMD CPU draws more power (and therefore heats up my room) more then my Intel setup. That wasn’t an outcome I was expecting, but then again I was only looking at peak, not idle, numbers at the time.

I really hope AMD can start bringing their idle power consumption down in this next gen.

Can you give some details (components and consumption)? I'm interested in the topic, and I've done some wall measurements as well, in the past and present.

My 3900x is also very inefficient when idling. It never goes below 50w according to hwinfo64. My entire pc is surely above 100w idle.

Interesting, I'm currently running Windows 10 with a Ubuntu desktop in a VM and multiple web browsers open with lots of tabs. According to Ryzen Master, my 3900X is consuming ~25-30 watts.

Edit: Libre Hardware Monitor shows package consumption around ~55 watts which looks suspiciously close to CPU + chipset power consumption.

I have a 3950X and a 5950X. I thought it was the other components at first but then someone pointed me to the official Ryzem master software. It shows CPU package power, which has a persistently high floor consumption. Idle temps are also higher on the same cooler. It’s a well-known phenomenon on the forums when I searched.

FYI some programs really fuck with this, even at ""Idle"". On my ryzen 5 3600, it idles at a few watts, but if I open steam and just let steam idle on my library, the CPU now draws 15 watts.

My 5600G idles at 22W whole system (wall power). However it has the cheaper chipset, not the x prefixed one, no video card at the moment and just one NVMe ssd for storage. It does have 4 x 16 Gb ram sticks so you can go even lower if you get 2 x 32 i guess.

AM4 APUs are totally different from their CPU brethren and are much better behaved in this area, because they’re socketed versions of the mobile chips.

Interesting. My 3950x draws (wall power) approximately 67/68W in idle. I'm on a Bxxx chipset and a 6600 XT, which should both consume little in idle mode, and 3 SSD, which consume little.

I haven't read much, but it t seems the range of around 40/60W seems fairly normal in idle, for a modern system (both Intel/AMD). I remember a former system of mine consumed 32/33W though; I think it was an AMD 6800K.

Well I picked the 5600G because it was advertised as 65 W (well and because it allows me not to decide on a video card yet). Your CPU is advertised as 105 W. TDP is a lie these days but the lying should be proportional :)

At a quick google, the 6600 xt idles at 4W with one monitor but at 20 W with two! Plus whatever extra power the motherboard needs to keep that pcie slot active.

Two extra ssds may consume little but that can be like 4-5 W more. It all adds up.

Over in Japan, Intel CPUs are sometimes fondly(?) called Idlemaster, which is a pun and reference to Idolmaster[1], for their superior idling performance. :V

[1]: https://en.wikipedia.org/wiki/The_Idolmaster

In Ryzen Master, my Ryzen 9 5900X is showing 11-13W CPU Power, 17W SOC Power.

It's largely idle, just lots of background stuff/open programs (VS Code, Discord, Excel, Firefox, Teams, Edge, MySQL Workbench, Thunderbird, Messenger, Outlook.)

PPT is 30% of 142W = 42.6 W. (Not sure what PPT stands for.)

EDIT: https://www.gamersnexus.net/guides/3491-explaining-precision...

> Package Power Tracking (“PPT”): The PPT threshold is the allowed socket power consumption permitted across the voltage rails supplying the socket.

IIUC, this is mainly because the IO die was made on 14nm. With Zen 4 moving to 7nm for IO die, I think lower idle power draw is expected. We'll see by how much soon.

It’s not just the IO die, but also IF on AM4 seemingly not supporting power management - it always runs at full speed, unsurprisingly a bus that fast burns a lot of power.

Does this apply also to laptop parts?

Yes, and even moreso for the laptop/mobile CPUs because those generally tend to have more E-cores than P-cores compared to the desktop CPUs, which further reduces power use in exchange for less absolute performance.

Every comparison I've seen between Ryzen 5000/6000 laptops and Alder Lake laptops has AMD winning battery life by a wide margin. Intel may want you to believe their E cores are enough to win the efficiency battle, but in practical use, they aren't doing enough.

No it doesn't. Unlike desktop parts the mobile chips are single die, it's the separate IO die which seems to be the primary reason for the high idle draw. Current gen AMD mobile chips are pretty much even with Intel at idle and significantly more efficient under any load metric.

This is true, it seems like the infinity fabric limits how low AMD cpus can idle. Intel invested pretty heavily in power saving tech during their 4 core

One other thing that hurts AMD here was the x570 chipset. It seems to be a hack job, basically installing the I/O from the CPU upside down and running it as a chipset. IIRC it uses like double the wattage of the x470 chipset it replaced.

I see the same thing in Intel vs AMD servers, AMDs are like 3x the power on idle

It seems quite unlikely that the idle power draw difference between Intel and AMD is doing anything at all to your room. The chiplet design is hurting AMD's idle power, but it's still going to be far from a "large" difference. Your monitor is probably using more power than an idling Ryzen CPU is.

Reply on news.ycombinator.com