*** AMD "Zen" thread (inc AM4/APU discussion) ***

[humbug]

Ah yes, AMD using some fine magic to squeeze 45W of electrical power worth of iGPU in a 15W TDP package... Are you serious???

It still less than the Intel system and you clearly do not understand TDP, it is not a measure of power consumption it is simply a recommendation for cooling, if this laptop has a 45 watt or higher rated cooler then the CPU / GPU firmware will allow it to go that high, if not it will throttle to keep within its cooling range, and i reiterate Prime95 and Furmark will push the CPU / GPU's much harder than any application and there in power consumption, the TDP ratings that Intel, AMD and nVidia have for their hardware are based on normal use, not Prime95 and Furmark.

Let me put it this way, my 4690K has an 86 watt TDP, if it puts out more than 86 watts of heat on a cooler with 86 watts of cooling efficiency it will throttle to reduce its power in order to remain within that 86 watt envelope, if not it will over whelm the cooler and over heat, its actually the heat its measuring which enable the system to function.,
Power is energy and energy used is converted into heat.

My 4690K is under a 250 watt cooler so its quit comfortable at 4.6Ghz pulling about 150 watts.

So what's happening with the AMD APU laptop is the cooling is at least adequate to allow it to pull 45 watt before it gets to its thermal throttling zone.

That is not magic, its how all modern hardware works.

 

[AndreiD]

You're making some fundamental mistakes in understanding how TDP works or is defined, you do get close to the definition there when you say that power does end up as heat, but then you get lost again.
RR is an ultrabook/ultrathin chip, they don't have the cooling to allow for the SKUs to massively exceed 25W TDP or even the lower 15W TDP. You're also ignoring the fact that notebookcheck measured abnormally high power consumption numbers (for a supposed 15W TDP part) for 3Dmark06 and The Witcher 3. They even state in their article that the RR APU is configured to 25W based on their measurements, so as I pointed out in my previous comments, not really a 1:1 comparison with the 15W Intel U parts, but again it's not a bad chip either since it has other advantages going for it.

And again, TDP is directly linked to power consumption when you take into consideration the thermal resistance of the package, that should be easy to understand for everyone.

 

[David Bisset]

You're mixing up design power with power use. Yes, power use is what generates heat and uses battery life, tests the cooling capacity.

TDP is design power, not power use. It merely indicates a likely envelope for power use that a cooler should account for. Yes, a mobo maker can choose to limit power draw to that (or less, or more) if they want, but that's their choice it's not what TDP is for or means.

It's a common mistake as it seems obvious that it tells us power use and indeed some try to calculate efficiency by TDP which is a significant misunderstanding. Within a product line you *may* be able to draw some inferences comparing TDP of parts but between products even from the same manufacturer it's a very approximate stick to try to measure power use by as it's not really what it means. There is no standard manufacturers must follow regarding when it'll hit that level of lower, when it'll draw more or less etc. Only wanting their parts to perform well with the coolers that end up on them forces any level of honesty.

 

[4K8KW10]

Well, guys, those chips rated at 95W TDP, pretty much take as much power from the mains.

 

[AndreiD]

@David Bisset All I'm saying is that power use is linked to TDP. You're right that TDP isn't a measure of power consumption, but it's not difficult to discern power consumption using TDP.
The power consumption of a chip like the 2500U shouldn't massively exceed an equivalent to 15W TDP unless it's been configured at a higher TDP than initially thought, that's all I've been trying to say and that notebookcheck article came to the same conclusion, that the 2500U was configured at 25W TDP.

For example, Intel defines TDP using (Tcase - Tambient) divided by the Tcase-to-Tambient thermal resistance coefficient. The temperature at the centre-top of the package, Tcase, is by definition directly proportional to power consumption. AMD's definition is fairly similar, (Tcase-Tambient) divided by a thermal resistance coefficient.

 

[4K8KW10]

It is because every chip has its own unique power consumption. The TDP is a summary in order to get a clue about approximately how much in reality it is.

 

[DragonQ]

Well, guys, those chips rated at 95W TDP, pretty much take as much power from the mains.

AMD's chips do at least.

 

[humbug]

@AndreiD You keep saying you understand TDP is not power consumption and then equating TDP to power consumption, how many times are people going to have to tell you TDP IS NOT THE CPUs POWER CONSUMPTION

The 15 watt Intel system used 50 watts under Prime95 and Furmark load; The later is its power consumption under Prime95 and Furmark load.
The 15 watt AMD system used 45 watts under Prime95 and Furmark load; The later is its power consumption under Prime95 and Furmark load.

15 watts TDP does not = 15 watts power consumption

Look: Core i9-7900X "TDP 140 watts" Power consumption under Prime95 230 Watts.

Now YOU explain that ^^^^^

I have, right here, your reasoning has got'a be different so what is it?

It still less than the Intel system and you clearly do not understand TDP, it is not a measure of power consumption it is simply a recommendation for cooling, if this laptop has a 45 watt or higher rated cooler then the CPU / GPU firmware will allow it to go that high, if not it will throttle to keep within its cooling range, and i reiterate Prime95 and Furmark will push the CPU / GPU's much harder than any application and there in power consumption, the TDP ratings that Intel, AMD and nVidia have for their hardware are based on normal use, not Prime95 and Furmark.

Let me put it this way, my 4690K has an 86 watt TDP, if it puts out more than 86 watts of heat on a cooler with 86 watts of cooling efficiency it will throttle to reduce its power in order to remain within that 86 watt envelope, if not it will over whelm the cooler and over heat, its actually the heat its measuring which enable the system to function.,
Power is energy and energy used is converted into heat.

My 4690K is under a 250 watt cooler so its quit comfortable at 4.6Ghz pulling about 150 watts.

So what's happening with the AMD APU laptop is the cooling is at least adequate to allow it to pull 45 watt before it gets to its thermal throttling zone.

That is not magic, its how all modern hardware works.

 

[AndreiD]

@humbug I literally gave you Intel & AMD's definition of TDP and how it is linked to power consumption.

And I linked you above to an article on why the 7900X blows way past its TDP wtih some motherboards. The Tomshardware article used an MSI motherboard and MSI motherboards have the TDP limits removed in their firmware.
Not to mention your own image shows the 6950X and 6900K sticking to their 140W TDP limit pretty faithfully, if you factor in the thermal resistance that 145W/148W power consumption is probably 140W TDP exactly. This also goes back to the Intel Turbo Boost Technology discussion from the Coffee Lake thread, under normal circumstances that 7900X should be limited by its 140W TDP and the equivalent power consumption when factoring in thermal resistance, but motherboard firmware removed that limit.

The 15 watt Intel system used 50 watts under Prime95 and Furmark load; The later is its power consumption under Prime95 and Furmark load.
The 15 watt AMD system used 45 watts under Prime95 and Furmark load; The later is its power consumption under Prime95 and Furmark load.

Correction:
The 15W TDP Intel CPU + 25W TDP Nvidia GPU laptop used ~50W in 3 different scenarios: Prime95&Furmark, The Witcher 3 and 3DMark06.
The 25W cTDP (possibly higher) AMD APU laptop used ~45W in the same 3 different scenarios.
There are other components that obfuscate real chip power usage (because if you read the article you'd notice that notebookcheck measured power for the entire laptop), but it's safe to say notebookcheck aren't far off in their suspicion that the 2500U is set to 25W TDP.

 

[humbug]

How are you or i overcloking our CPU's with locked to TDP ratings, @AndreiD ?

My CPU is pulling about 150 Watts, it has an 86 Watt TDP rating, my motherboard is not an MSI, Its a Gigabyte, everyone with overclocked CPU's are pulling higher power than their TDP rating.

The other CPU's on that chart are just far more efficient than the 7900X, all of them other than the older 69xx series and 6 core 95 Watt 1600X are over TDP.

The 1800X/1700X also have a 95 Watt TDP, but they are 8 core and using ~118
The 7700K has a 91 Watt TDP, it is using 114 Watts.

The 7900X due to Intel clocking the crap out of it (to keep it competitive AMD's 1920X) all its efficiency is out of the window, that's why its so high, at least under Prime95, its not that high under normal use, non of them are.

Also way over its TDP Asus X299 System draw 300 Watts with Cinebench https://www.kitguru.net/components/...900x-skylake-x-10c20t-cpu-indepth-analysis/9/

I can find power levels like that ^^^^ all day and none on MSI boards.

 

[humbug]

How are you or i overcloking our CPU's with locked to TDP ratings, @AndreiD ?

My CPU is pulling about 150 Watts, it has an 86 Watt TDP rating, my motherboard is not an MSI, Its a Gigabyte, everyone with overclocked CPU's are pulling higher power than their TDP rating.

The other CPU's on that chart are just far more efficient than the 7900X, all of them other than the older 69xx series and 6 core 95 Watt 1600X are over TDP.

The 1800X/1700X also have a 95 Watt TDP, but they are 8 core and using ~118
The 7700K has a 91 Watt TDP, it is using 114 Watts.

The 7900X due to Intel clocking the crap out of it (to keep it competitive AMD's 1920X) all its efficiency is out of the window, that's why its so high, at least under Prime95, its not that high under normal use, non of them are.

Also way over its TDP Asus X299 System draw 300 Watts with Cinebench https://www.kitguru.net/components/...900x-skylake-x-10c20t-cpu-indepth-analysis/9/

I can find power levels like that ^^^^ all day and none on MSI boards.

Another one, 260 Watts Cinebench, ASRock this time.... https://www.techspot.com/review/1433-intel-core-i9-core-i7-skylake-x/page4.html

Over 400 Watts overclocked https://www.techspot.com/review/1437-overclocking-core-i9/

140 Watt TDP

 

[4K8KW10]

Prime95 is a power virus. Doesn't count under normal circumstances. The same with Furmark. Highly recommended to avoid both.

 

[gavinh87]

So much anger in this thread

 

[4K8KW10]

AMD's chips do at least.

Actually, Ryzen is more power efficient than i7s.

 

[gavinh87]

Actually, Ryzen is more power efficient than i7s.

At the same clockspeeds?

 

[AndreiD]

@humbug You said your CPU is overclocked so no wonder it's pulling that much power, do you think TDP limits are enforced when overclocking? Also if you're using software like HWInfo64 note that it's going to report an estimate which isn't going to be very accurate.

I don't want to go back to the same point over and over again, but like I've said and linked articles to back my claim up, some motherboards completely removed the TDP limit for the 7900X by default and that's the reason why some outlets measured abnormal power consumption figures.
https://www.anandtech.com/show/1155...-core-i9-7900x-i7-7820x-and-i7-7800x-tested/8

Anandtech also used Prime95 and they measured close to TDP power consumption figures for the 7900X/7800X. I don't understand why you're even clinging to this so much because you were commenting quite a lot in that MCE thread and you should know that desktop platforms have various options which remove the various CPU package limits.

 

[AndreiD]

Actually, Ryzen is more power efficient than i7s.

Depends on the workload & CPUs you compare:
https://techreport.com/review/32607/intel-core-i9-7980xe-and-core-i9-7960x-cpus-reviewed/13
That being said, it's definitely a huge leap for AMD considering their previous CPU line.

 

[humbug]

@humbug You said your CPU is overclocked so no wonder it's pulling that much power, do you think TDP limits are enforced when overclocking? Also if you're using software like HWInfo64 note that it's going to report an estimate which isn't going to be very accurate.

I don't want to go back to the same point over and over again, but like I've said and linked articles to back my claim up, some motherboards completely removed the TDP limit for the 7900X by default and that's the reason why some outlets measured abnormal power consumption figures.
https://www.anandtech.com/show/1155...-core-i9-7900x-i7-7820x-and-i7-7800x-tested/8

Anandtech also used Prime95 and they measured close to TDP power consumption figures for the 7900X/7800X. I don't understand why you're even clinging to this so much because you were commenting quite a lot in that MCE thread and you should know that desktop platforms have various options which remove the various CPU package limits.

It's like arguing to a brick wall at this point, not sure why I'm even wasting my own time.

Slide wars.... According to them all those CPU's are at or below TDP, its an anomaly but not necessarily an incorrect one, perhaps they are using completely different settings to just about everyone else, certainly AMD's 8 core Ryzen look's ####'ing astonishing at 65 Watts under prime95 right at the top of the slide, if you were to look at that on its own at least, but then you see the rest of the slide and see what's going on, they all fit neatly at or below their TDP rating, yeah, its almost flawless.

I can certainly see how seeing a slide like that would lead one to believe TDP is directly related to power consumption, why do we even bother to test for power consumption? i mean its written right there on the box right?

 

[humbug]

Slide wars.... According to them all those CPU's are at or below TDP, its an anomaly but not necessarily an incorrect one, perhaps they are using completely different settings to just about everyone else, certainly AMD's 8 core Ryzen look's ####'ing astonishing at 65 Watts under prime95 right at the top of the slide, if you were to look at that on its own at least, but then you see the rest of the slide and see what's going on, they all fit neatly at or below their TDP rating, yeah, its almost flawless.

I can certainly see how seeing a slide like that would lead one to believe TDP is directly related to power consumption, why do we even bother to test for power consumption? i mean its written right there on the box right?

I'll put it this way, anyone here with a Ryzen 1700, put it back to stock and see how much you have to kerfuie around with Prime95 to get it to only sip 65 Watts, or maybe just ask Anand how they did it.

I know Anand is a trusted name from old but we used to think that about politics.

Its 15 Watts more than your Intel Laptop @AndreiD 15 watts, its an 8 core Desktop CPU, do you really take that slide at face value?

 

[AndreiD]

There's a lot of variation when it comes to motherboard firmware and how they handle the various CPU package limits, even on Ryzen you have various options for it (like ASUS with Performance Bias).

And here's the technical definition of TDP according to AMD:
TDP = (Tcase°C - Tambient°C) / (Heatsink ϴca)
Where Tcase°C is the temperature at the top-center of the CPU package, Tambient is self explanatory and Heatsink ϴca is an AMD coefficient for heatsink performance.
The key variable is Tcase°C which is = Tjunction - (ΨJT * POWER), which reads as junction temperature (Tambient + (θJA * Power)) minus thermal resistance that dissipated some of the heat. It's not difficult to notice that Tcase is directly proportional with power, so just because Power isn't in the TDP equation doesn't mean that the two aren't linked. Electrical watts when taking into account thermal resistance = thermal watts...