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GMP damaging Zen 5 CPUs?

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Re: GMP damaging Zen 5 CPUs?

#171

Post by magicalhippo »

db48x wrote: post #80
wahern wrote: post #60

Earlier quoted context omitted.

That seems a little too cynical. It matters how a customer might use a chip, such as the type of cooling that would be expected in a typical system using that model, and that's informed by the advertised specifications. Base clocks and the amount of SRAM also figure into TDP. No doubt there are completely arbitrary aspects to TDP driven purely by profit-focused market segmentation, but it's not just that. That said,…

No, clock speed and cache have nothing to do with TDP. AMD uses a simple formula to calculate TDP. It is the temperature of the IHS minus the air temperature measured at the cpu cooler’s intake fan, divided by a conversion faction in °C/W. But they don’t use real temperatures from real systems. They just make up a different set of temperatures for each CPU that they sell, so that the TDP comes out to the number that…

> The formula doesn’t even mean anything, in real physical terms.

From your description the formula is how you would calculate the power for which a certain heatsink at a given ambient temperature would result in the specified IHS temperature.

The °C/W number is not a conversion factor but the thermal resistance[1] of the heatsink & paste, that is a physical property.

So unless I misunderstood you it's very much something real in physical terms.

[1]: https://fscdn.rohm.com/en/products/databook/applinote/common...

Re: GMP damaging Zen 5 CPUs?

#172

Post by inferiorhuman »

Mistletoe wrote: post #168
mrheosuper wrote: post #122

Earlier quoted context omitted.

When something is uploaded to the internet, it won't be easy to take it down. Ask Beyonce.

Can you explain further about Beyoncé? Do you mean the elevator video where her sister attacks Jay Z?

http://i.imgur.com/oyUfxWE.jpg

Re: GMP damaging Zen 5 CPUs?

#173

Post by munchlax »

userbinator wrote: post #121
spoaceman7777 wrote: post #101

Earlier quoted context omitted.

All you really need to see is the picture of the CPU with thermal paste only on one half. Thermal throttling is tuned to work when there is 1. a sufficient heatsink (theirs was significantly below requirements) and 2. it is installed correctly so that its triggers for downclocking happen with the correct timing. This is just another instance of ridiculous PEBCAK error

I'm not as sure about AMD CPUs (and they were known for having far worse overheat behaviour back in the early 2000s) but there are plenty of stories of Intel CPUs working for many years, sitting at the thermal limits, with the (stock) heatsink not even in contact, thanks to their cheap push-pin retention mechanism.

Those dreadful plastic knobs never want to sit right. Simple lever over that shit any time of day, pls.

Re: GMP damaging Zen 5 CPUs?

#174

Post by bob1029 »

userbinator wrote: post #126
bob1029 wrote: post #9

Could be the power supply and load profile? I've heard some really wild noises coming out of my zen4 machine when I've had all cores loaded up with what is best described as "choppy" workloads where we are repeatedly doing something like a parallel.foreach into a single threaded hot path of equal or less duration as fast as possible. I've never had the machine survive this kind of workload for more than 48 hours with…

I've never had the machine survive this kind of workload for more than 48 hours without some kind of BSOD. Then you shouldn't trust the results of your work either, as that's indicative of a CPU that's producing incorrect results. I suggest lowering the frequency or even undervolting if necessary until you get a stable system. ...and yes, wildly fluctuating power consumption is even more challenging than steady-state…

The results might be invalid for one generation but the model is resilient to these kinds of events overall. Far more resilient than my operating system is.

Randomly flipped genome bits could even be beneficial for escaping local minima and broken RNG in evolutionary algorithms. One bad evaluation won't throw the whole thing off. It's gotta be bad constantly.

Re: GMP damaging Zen 5 CPUs?

#175

Post by menaerus »

db48x wrote: post #132
gruez wrote: post #91

Earlier quoted context omitted.

>But the TDP doesn’t have anything to do with how much power the cpu will draw or how much heat it will generate in practice. Those numbers vary quite a lot; the CPU continuously adjusts it’s own frequency multiplier based on it’s own measured temperature, meaning it’ll draw more power if you cool it better. I don't get it, are you referring to the phenomenon that different workloads have different power consumption…

No, the TDP number doesn’t even vaguely approximate anything. You can’t use the number to predict anything, or to plan, or to estimate your electric bill, or anything like that.

Isn't TDP supposed to be an upper bound of how much power budget there is for a chip when it's running under maximum IPC (which implies AVX512 workload spread across all cores with all the test data in all the L1 caches)? I guess that power budget can vary due to process imperfections and/or CPU bugs but saying that it doesn't approximate anything is hard to believe. How about the PSU then, e.g. is 800W PSU a made-up number as well?

Re: GMP damaging Zen 5 CPUs?

#176

Post by Michvalwin »

About two months ago My 9950X3D died. I presume it the memory controller died because my asus board reported a ram problem. It was with a 2x48GB 6000 ram. Which was not supported by the board (at least on the docs). I also limited the max PBO by 400Mhz and limited VDDIO to 1.3V. But it still died while shutting down cachyOS.

Re: GMP damaging Zen 5 CPUs?

#177

Post by account42 »

trebligdivad wrote: post #74
topspin wrote: post #4

As there is ongoing drama with Zen 5 and power issues, there are people with the instruments and the motivation to investigate this. You should consider contacting Gamers Nexus, and help them to get your test suite running. They can measure power draw and do a thermal analysis of this CPU, and they'd likely be eager to do it, given the possibility of making a bunch of dramatic YouTube content about design flaws in wi…

They don't say what temperature the CPU was reporting which seems like an odd omission. Whatever the specs of your cooler etc check the temperature it's actually running at. Go by what the CPU is saying! I've got the older 3950x, and the first one died after a few months (still in warranty) with a cooler in spec, but it would go into the 90s at full load just doing big builds. I replaced the heatsink with a basic wat…

Zen 2 is supposed to be able to work up to 95 C so that shouldn't have caused your CPU to fail. And it should clock down before it fails anyway, way below the specified "minimum" frequency if needed - got to experience that with a failing AIO. A better cooler should only be required to make full use of your CPU not to protect it.

Re: GMP damaging Zen 5 CPUs?

#178

Post by account42 »

johncolanduoni wrote: post #107
bayindirh wrote: post #71

Earlier quoted context omitted.

When I see the term TDP, I remember what I have read in the "Thermal Design Document" of Intel Core2Quad Q6600 and the family it belongs: > The thermal solution bundled with the CPUs is not designed to handle the thermal output when all the cores are utilized 100%. For that kind of load, a different thermal solution is strongly recommended (paraphrased). I never used the stock cooler bundled with the processor, but w…

Most states of “100% utilization” as you’d see in `top` are not 100% thermal output or even close. Cores waiting for memory accesses count as utilized in the former sense but will not produce as much heat as one that is actually using the ALU etc. That’s why special make-work like Prime95 is used for stress testing overclocking/thermals: it will saturate the cores with enough unblocked arithmetic work to generate mor…

You're not going to get anywhere near full thermal load with just integer arithmetic either - you need to saturate the floating point units for that.

Re: GMP damaging Zen 5 CPUs?

#179

Post by edgineer »

"We don't overclock or overvolt or play other teen games with our hardware."

You overclock as a teen so that as an adult you know to verify your CPU's voltage, clock speeds, and temperature at a minimum when you build your own system.

They made no mention of monitoring of CPU temperature, ECC corrected/detected errors, or throttling. They then ran CPU benchmark loads for several months on the system.

"The so-called TDP of the Ryzen 9950X is 170W. The used heat sinks are specified to dissipate 165W, so that seems tight."

Yikes. You need a heatsink rated much higher. These CPUs were overheated for months.

Re: GMP damaging Zen 5 CPUs?

#180

Post by account42 »

mrheosuper wrote: post #164
RachelF wrote: post #125

Earlier quoted context omitted.

Yes, this is the point - software should never be able to physically damage the hardware it is on. If it can, then the hardware is to blame.

As a FW engineer, my software has released the magic smoke a lot.

That's why firmware is often considered a separate category from software even though technically it's the same thing. Software is code that expects the hardware to works as specified, firmware is what achieves that.
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