Discussion Speculation: Zen 4 (EPYC 4 "Genoa", Ryzen 7000, etc.)

[Vattila]

Except for the details about the improvements in the microarchitecture, we now know pretty well what to expect with Zen 3.

The leaked presentation by AMD Senior Manager Martin Hilgeman shows that EPYC 3 "Milan" will, as promised and expected, reuse the current platform (SP3), and the system architecture and packaging looks to be the same, with the same 9-die chiplet design and the same maximum core and thread-count (no SMT-4, contrary to rumour). The biggest change revealed so far is the enlargement of the compute complex from 4 cores to 8 cores, all sharing a larger L3 cache ("32+ MB", likely to double to 64 MB, I think).

Hilgeman's slides did also show that EPYC 4 "Genoa" is in the definition phase (or was at the time of the presentation in September, at least), and will come with a new platform (SP5), with new memory support (likely DDR5).

What else do you think we will see with Zen 4? PCI-Express 5 support? Increased core-count? 4-way SMT? New packaging (interposer, 2.5D, 3D)? Integrated memory on package (HBM)?

Vote in the poll and share your thoughts!

 

[gdansk]

My problem with 95C is the fan curves. Before I could easily run my CPU fans at say 70% even when rendering with nearly 100% load. But now they do go up to 100% speed which is noticeably louder. I could set the fan curve to max out at 70% but it's probably better to set the thermal target toward that area of the fan speed vs temperature curve. In either case it is effectively throttling.

 

[repoman0]

Well my problem with 95C is the fan curves. Before I could easily run my CPU fans at say 70% even when rendering with nearly 100% load. But now they do go up to 100% speed which is noticeably louder.

Change the maximum fan speed at 95C to whatever noise level you choose to tolerate. Nothing says it has to be 100%. I set mine to 70

 

[Timmah!]

Change the maximum fan speed at 95C to whatever noise level you choose to tolerate. Nothing says it has to be 100%. I set mine to 70

Then it will downclock, right?

 

[Mopetar]

While that's true, you can conflate power draw and heat output. If your CPU is drawing 100 watts, you know it is emitting 100 watts of heat into the ambient environment around your PC.

I agree with those who say 95C isn't a problem. If the CPU is rated for continuous operation at that temperature without compromising its life (at least not beyond the time you plan to use it) then who cares? What matters is the PC's total power draw, because that's what impacts your power bill and may heat up the room in which the PC resides to an uncomfortable level.

What if CPUs were made with a different material that allowed them to operate at 300C, would people complain about that? If it had the same lifetime, and the same overall power draw, why should you care if a small spot on the die was 300C or 95C or only 35C?

I think it's mainly just people being squeamish for historical reasons. Most parts weren't designed to run a that temperature 24/7 and you could fry a chip if it got too hot before companies added heat sensors to throttle performance in those cases. Even though this hasn't been the case in a long while, it's one of those things that still makes people a little uncomfortable.

Once you start getting hotter though, the risk of fire does increase. 95 C isn't terribly dangerous, but 300 C seems like it could be unless you're careful at what comes into contact with the CPU or cooling solution. I'd aim for 400 C though so you could just use it to run a fryer. Then you'd have an even better version of the KFC computer.

 

[Atari2600]

Uh, really? Then consider me one generally misunderstanding how this works and in need of explanation.
Cause from my layman view and empirical observation, the fan speed tends to generally increase as the temperature of the chip the fan is supposed to cool down, rises.

It's called newton's law of cooling.

Go Google it.

The point made about it being easier to cool the same thermal load with a higher delta T is completely irrelevant to your fan speeds.

 

[Atari2600]

96 Core Genoa vs 96 Core Sapphire Rapids.

What was power consumption like?

 

[Doug S]

I think it's mainly just people being squeamish for historical reasons. Most parts weren't designed to run a that temperature 24/7 and you could fry a chip if it got too hot before companies added heat sensors to throttle performance in those cases. Even though this hasn't been the case in a long while, it's one of those things that still makes people a little uncomfortable.

Once you start getting hotter though, the risk of fire does increase. 95 C isn't terribly dangerous, but 300 C seems like it could be unless you're careful at what comes into contact with the CPU or cooling solution. I'd aim for 400 C though so you could just use it to run a fryer. Then you'd have an even better version of the KFC computer.

Not really, if the CPU is still only drawing 100 watts (or whatever figure) that's all the heat it can contribute to a fryer. Doesn't make any difference if one spot is 95C or 400C. You'd never get the oil hot enough to cook a wing with only 100 watts, at least not in an open air oil fryer like restaurants use.

I wouldn't worry about fires either. A 400C hot spot on a CPU would start a fire if it comes in contact with a piece of paper, but how exactly is paper going to get underneath the CPU? The top of the die on the heat spreader wouldn't reach anywhere near that temperature, let alone the heat sink/fan or cooling fluid (if using some type of liquid cooling) because again, it is only dispersing 100 watts of heat.

If a 400C die temperature allowed for CPUs that draw 4000 watts then maybe it is a concern, but almost no one would want to operate such a thing in their home anyway.

 

[RnR_au]

Then it will downclock, right?

Yeah. Noise vs power. Don't like the noise? Upgrade your cooling or activate ECO.

 

[Saylick]

I think it's mainly just people being squeamish for historical reasons. Most parts weren't designed to run a that temperature 24/7 and you could fry a chip if it got too hot before companies added heat sensors to throttle performance in those cases. Even though this hasn't been the case in a long while, it's one of those things that still makes people a little uncomfortable.

Once you start getting hotter though, the risk of fire does increase. 95 C isn't terribly dangerous, but 300 C seems like it could be unless you're careful at what comes into contact with the CPU or cooling solution. I'd aim for 400 C though so you could just use it to run a fryer. Then you'd have an even better version of the KFC computer.

AMD needs to hire you for their marketing department.

 

[gdansk]

Yeah. Noise vs power. Don't like the noise? Upgrade your cooling or activate ECO.

Wasn't an issue last generation

 

[DrMrLordX]

On AM5, is reporting software providing "hotspot" temps or . . . ? Cuz that was an issue with a lot of their N7 products. Radeon VII reported both temps and the differences were staggering to say the least.

 

[Doug S]

On AM5, is reporting software providing "hotspot" temps or . . . ? Cuz that was an issue with a lot of their N7 products. Radeon VII reported both temps and the differences were staggering to say the least.

You can only report where there are sensors, but if you add more sensor locations and report the highest number...

 

[Kocicak]

Intel Sapphire Rapids-SP 4S Mother Board
View attachment 68212

I already commented elsewhere, that this motherboard appears to have an ideal size to be integrated in a cooktop.

Directly using ample waste heat of modern computer equipment to prepare food is a way forward IMO. We need computer case, motherboard, graphic card and cooking equipment manufacturers to cooperate to come up with solutions consumers would really benefit from.

Imagine a computer with a rice cooker built in. Or hot dog maker. Pop corn machine, anyone?

 

[Timorous]

I already commented elsewhere, that this motherboard appears to have an ideal size to be integrated in a cooktop.

Directly using ample waste heat of modern computer equipment to prepare food is a way forward IMO. We need computer case, motherboard, graphic card and cooking equipment manufacturers to cooperate to come up with solutions consumers would really benefit from.

Imagine a computer with a rice cooker built in. Or hot dog maker. Pop corn machine, anyone?

Alternatively connect it to an underfloor heating system as a secondary heat source for the winter.

 

[igor_kavinski]

Alternatively connect it to an underfloor heating system as a secondary heat source for the winter.

Hey, that gave me a brilliant idea! We could use a water bed as a giant passive radiator. Perfect for winter and in summer, not bad to use as a sauna

 

[DrMrLordX]

You can only report where there are sensors, but if you add more sensor locations and report the highest number...

Zen has had elaborate networks of sensors since the start.

Zen - Microarchitectures - AMD - WikiChip

Zen (family 17h) is the microarchitecture developed by AMD as a successor to both Excavator and Puma. Zen is an entirely new design, built from the ground up for optimal balance of performance and power capable of covering the entire computing spectrum from fanless notebooks to high-performance...

en.wikichip.org

A larger number of sensors across the entire die are used to measure many of the CPU states including frequency, voltage, power, and temperature. The data is in turn used for workload characterization, adaptive voltage, frequency tuning, and dynamic clocking. Adaptive voltage and frequency scaling (AVFS), an on-die closed-loop system that adjusts the voltage in real time following real-time measurements based on sensory data collected. This is part of AMD's "Precision Boost" technology offering high granularity of 25 MHz clock increments.

Zen implements over 1300 sensors to monitor the state of the die over all critical paths including the CCX and external components such as the memory fabric. Additionally the CCX also incorporates 48 high-speed power supply monitors, 20 thermal diodes, and 9 high-speed droop detectors.

 

[Abwx]

Zen has had elaborate networks of sensors since the start.

Zen - Microarchitectures - AMD - WikiChip

Zen (family 17h) is the microarchitecture developed by AMD as a successor to both Excavator and Puma. Zen is an entirely new design, built from the ground up for optimal balance of performance and power capable of covering the entire computing spectrum from fanless notebooks to high-performance...

en.wikichip.org

You ll notice that Intel s DLVR wich is tooted as a great innovation is already present in Zen 1...

 

[eek2121]

My problem with 95C is the fan curves. Before I could easily run my CPU fans at say 70% even when rendering with nearly 100% load. But now they do go up to 100% speed which is noticeably louder. I could set the fan curve to max out at 70% but it's probably better to set the thermal target toward that area of the fan speed vs temperature curve. In either case it is effectively throttling.

If the noise of 100% bothers you, definitely reduce the fan speed.

I agree, however, that it appears to go against current cooling methodology. I am beginning an ITX build today in a very small case. Will definitely report back on noise + thermals.

I already commented elsewhere, that this motherboard appears to have an ideal size to be integrated in a cooktop.

Directly using ample waste heat of modern computer equipment to prepare food is a way forward IMO. We need computer case, motherboard, graphic card and cooking equipment manufacturers to cooperate to come up with solutions consumers would really benefit from.

Imagine a computer with a rice cooker built in. Or hot dog maker. Pop corn machine, anyone?

I am surprised companies haven’t come up with a way to utilize that waste heat. Integrate a coffee maker! 🤣

 

[igor_kavinski]

Someone somewhere is furiously drawing up patent applications as we speak...

 

[Kocicak]

We publicly disclosed the idea, it is not possible to patent it anymore. Now everybody can make these without any limit.

Coffee maker is an obvious use, and temperature-wise easily doable.

BTW a good air humidifier is the kind which boils water (it is much better than those ultrasonic ones, which leave residue in the air after the tiny droplets evaporate), but they are not usually used due to the high energy draw. Now they can be used again, while cooling computers. This all so wonderful!

 

[In2Photos]

You ll notice that Intel s DLVR wich is tooted as a great innovation is already present in Zen 1...

Heh heh, he said "tooted".

 

[igor_kavinski]

Now they can be used again, while cooling computers. This all so wonderful!

Humidifier in the same room as the PC? Isn't that inviting accelerated rusting of PC components? I lost a dear 486 to an air cooler. The humidity mixed with the dust on the motherboard gave rise to mold growth that probably caused a short circuit.

 

[Kocicak]

....the humidity mixed with the dust on the motherboard gave rise to mold growth that probably caused a short circuit.

I never grow mushrooms in my computers.

There is a serious problem with dry air in living areas during winter - making a cpu cooler as an opened vessel for boiling water is extremelly simple. You just need some simple valve with float to let more water in when the water level drops, also you can fit some overflow drain to prevent disaster in case the valve failed.

 

[igor_kavinski]

There is a serious problem with dry air in living areas during winter -

Yeah, a controlled humidifier using the CPU heatsink that never increases the humidity above a safe level would not be a bad idea.

 

[Timmah!]

I already commented elsewhere, that this motherboard appears to have an ideal size to be integrated in a cooktop.

Directly using ample waste heat of modern computer equipment to prepare food is a way forward IMO. We need computer case, motherboard, graphic card and cooking equipment manufacturers to cooperate to come up with solutions consumers would really benefit from.

Imagine a computer with a rice cooker built in. Or hot dog maker. Pop corn machine, anyone?

Cooktop is good idea. Additionally, to prepare food while traveling i suggest notecook.