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]

Ah, so it's wrong because it's not what you want? Got it! How dare AMD!

No, it's wrong because it's the opposite of all Zen behavior hither to. I'll reiterate my stance:

1. It's the opposite of XMP which is opt-in for possible instability.
2. It's the opposite of Zen 1-3 which were opt-in for inefficiency.
3. Zen 4 is clearly optimized for far less power per core. Their own slides show this and its backed by benchmarks.
4. It's the default because they didn't want to lose both 1T and MT to Raptor Lake. That's why Robert had to backtrack his 170W comment.

I don't blame AMD but it should be recognized as the Intel-like benchmark chasing it is. And I bought the 7950X because Computerbase and other competent reviewers did test at reasonable power limits.

 

[maddie]

No, it's wrong because it's the opposite of all Zen behavior hither to. I'll reiterate my stance:

1. It's the opposite of XMP which is opt-in for possible instability.
2. It's the opposite of Zen 1-3 which were opt-in for inefficiency.
3. Zen 4 is clearly optimized for far less power per core. Their own slides show this and its backed by benchmarks.
4. It's the default because they didn't want to lose both 1T and MT to Raptor Lake. That's why Robert had to backtrack his 170W comment.

I don't blame AMD but it should be recognized as the Intel-like benchmark chasing it is. And I bought the 7950X because Computerbase and other competent reviewers did test at reasonable power limits.

Live a little, try something different.

 

[In2Photos]

No, it's wrong because it's the opposite of all Zen behavior hither to. I'll reiterate my stance:

1. It's the opposite of XMP which is opt-in for possible instability.
2. It's the opposite of Zen 1-3 which were opt-in for inefficiency.
3. Zen 4 is clearly optimized for far less power per core. Their own slides show this and its backed by benchmarks.
4. It's the default because they didn't want to lose both 1T and MT to Raptor Lake. That's why Robert had to backtrack his 170W comment.

I don't blame AMD but it should be recognized as the Intel-like benchmark chasing it is. And I bought the 7950X because Computerbase and other competent reviewers did test at reasonable power limits.

Well it also has a different socket, a different heat spreader, a different memory requirement, etc compared to previous generations. Where's the outrage over that?
And there is no instability out of the box on the chip. It just runs hotter!!!

 

[gdansk]

Well it also has a different socket, a different heat spreader, a different memory requirement, etc compared to previous generations. Where's the outrage over that?
And there is no instability out of the box on the chip. It just runs hotter!!!

Those are all more complicated changes than a picking different defaults. Sensible defaults would have almost no impact except that people who just want a fast workstation could have an out of the box experience that is pleasant. And benchmarkers could turn on the flamethrower mode. Running hot itself is only really a problem because of a series of compounding bad defaults. How many boards will default to 230W TDP, default to 95C thermal target, default fan profile of 100% at probably 70C?

I give AMD some credit for making eco mode so easy (with Ryzen Master). But I hated it when Intel allowed insane power limits to be the default and I hate it when AMD does it.

 

[moinmoin]

Maybe I'm wrong, but I still expect budget boards to appear eventually that don't support 170W TDP. In those boards the chips should be set accordingly lower by default.

 

[In2Photos]

Those are all more complicated changes than a picking different defaults. Sensible defaults would have almost no impact except that people who just want a fast workstation could have an out of the box experience that is pleasant. And benchmarkers could turn on the flamethrower mode. Running hot itself is only really a problem because of a series of compounding bad defaults. How many boards will default to 230W TDP, default to 95C thermal target, default fan profile of 100% at probably 70C?

What is preventing anyone from having a pleasant out of the box experience? Reviews have shown that you can put just about any cooler on it and get similar performance. With stock settings.

 

[gdansk]

Maybe I'm wrong, but I still expect budget boards to appear eventually that don't support 170W TDP. In those boards the chips should be set accordingly lower by default.

If true, that's another reason that all launch day reviews should have had 170W TDP and 105W TDP. A good number did try with eco modes.
Otherwise it may be a bit misleading for buyers of low end boards.

 

[gdansk]

What is preventing anyone from having a pleasant out of the box experience? Reviews have shown that you can put just about any cooler on it and get similar performance. With stock settings.

Did you try one? Let me tell you: it is not a pleasant out-of-the-box experience compared to last generation.

 

[Markfw]

Did you try one? Let me tell you: it is not a pleasant out-of-the-box experience compared to last generation.

Well, I have no problem, but it could be because I plan for the TDP of the CPU. One on a 420 AIO running 5 ghz all core, and one is a Be quiet Dark Rock pro 4 (air cooler rated at 250 watt tdp) running 5 ghz all core. All stock, but both running 95c. When I get my good memory and get everything setup, I will go to 170 watt tdp, but for now they are doing fine.

 

[gdansk]

Well, I have no problem, but it could be because I plan for the TDP of the CPU. One on a 420 AIO running 5 ghz all core, and one is a Be quiet Dark Rock pro 4 (air cooler rated at 250 watt tdp) running 5 ghz all core. All stock, but both running 95c. When I get my good memory and get everything setup, I will go to 170 watt tdp, but for now they are doing fine.

I'm running a Noctua NH-D15 and yes it will boost up to 5.1ghz all core out of the box. But it also ramps up to 100% fan speed opening Firefox. Obviously I changed it but I was talking about a series of compounding bad defaults and that's exactly what many will encounter. Especially anyone who buys a prebuilt with anything smaller than a 280mm AIO.

Luckily most people, these days, are savy enough to fix it. But it reminds me of Intel's MCE all over again.

 

[Saylick]

I'm running a Noctua NH-D15 and yes it will boost up to 5.1ghz all core out of the box. But it also ramps up to 100% fan speed opening Firefox. Obviously I changed it but I was talking about a series of compounding bad defaults and that's exactly what many will encounter. Especially anyone who buys a prebuilt with anything smaller than a 280mm AIO.

Luckily most people, these days, are savy enough to fix it. But it reminds me of Intel's MCE all over again.

Out of curiosity, what did you end up doing?

Did you keep the 95C limit and simply adjusted the fan curve such that it's not spinning at 100% at 95C? Or did you use a lower temperature limit which corresponded to a fan speed that was much quieter? ECO mode was also turned on?

 

[Markfw]

I'm running a Noctua NH-D15 and yes it will boost up to 5.1ghz all core out of the box. But it also ramps up to 100% fan speed opening Firefox. Obviously I changed it but I was talking about a series of compounding bad defaults and that's exactly what many will encounter. Especially anyone who buys a prebuilt with anything smaller than a 280mm AIO.

Luckily most people, these days, are savy enough to fix it. But it reminds me of Intel's MCE all over again.

Well, I will say that its possible under some circumstances that it could be noisey at stock. Since I am deaf to many things (except it seems fans) I could be wrong about some things. But when I get fan speeds, I set them all to full speed, and when I hit the NMVE and chipset fans, the noise was insane, so I set those to performance. Other than that they are all full speed and I can't hear them. And I do want to set like 90 or 85c as the target temp, when I get everything set.

 

[Harry_Wild]

AMD Ryzen 9 7950X Cooling Requirements & Thermal Throttling

High temperature seem to be an issue on the new Ryzen 7000 processors. We're pairing a Ryzen 9 7950X with a $10 stock cooler, a Noctua air-cooler and a 420 mm AIO to get a feel for what the differences are like in terms of °C, MHz and performance in both applications and games.

www.techpowerup.com

Does not matter what you uses as a cooler, stock remains at 95C! I would go with the $10 air cooler by AMD!

 

[gdansk]

Out of curiosity, what did you end up doing?

Did you keep the 95C limit and simply adjusted the fan curve such that it's not spinning at 100% at 95C? Or did you use a lower temperature limit which corresponded to a fan speed that was much quieter? ECO mode was also turned on?

I tried all three: limit PPT, set fan max speed to 70%, and set lower thermal target with a more normal fan curve where 80C is about 70%. For whatever reason the last solution did best in Davinci renders. So I'm running with that for now.

And I may add it is extremely pleasant when tamed.

 

[Saylick]

I tried all three: limit PPT, set fan max speed to 70%, and set lower thermal target with a more normal fan curve where 80C is about 70%. For whatever reason the last solution did best in Davinci renders. So I'm running with that for now.

And I may add it is extremely pleasant when tamed.

Thanks for the info. I haven't assembled my Zen 4 build yet (everything is still in their boxes) but wanted to know if someone figured out the optimal approach, and your solution was my first bet as well, i.e. if no cooler can prevent the processor from hitting the preset thermal target and because the relationship between temps and clocks is pretty much "inelastic", it made the most sense to me to simply set a lower thermal target and use a normal fan curve. Anywhere between 80C to 85C sounds like a good thermal target to use, too, considering that temperature range is what is conventionally deemed "safe".

 

[DisEnchantment]

The most annoying part for me about Ryzen 7000/X670E/AM5 are the long POST times, I get boot code 15 for almost 18 seconds before OS starts to load. I hope it is just something to do with my kit being XMP.

My 1700X was a mess with memory stability but at least it ran cool even with a Noctua Low profile NH-L9x65 Air Cooler. Very quiet. And compiling code on Zen1 cause the compiler to crash when using a lot of threads, was a known problem for a while.
My 3900X has temp spikes which I hate a lot and the AM4 B550 AGESA has no option to throttle the peak temperature because a small boost is enough to send the AIO pump and fans crazy. Memory support was flaky but it got to 3200CL14
Things were very improved on 5950X and X570, the BIOS is quite mature, memory speed and stability is top notch, but not having the possibility to control spikes still irked me a lot. Temps and fans/pumps whirring bothered me.
On top of that I tried Noctua Low noise padded fans and Corsair PWM Maglev Rad fans.
Because of all of these, I operate these chips in ECO mode.

On my X670E, once I set the Tjmax to 80, everything is so quiet and cool. This is the best Ryzen chip for me.
With Corsair Maglev PWM Case and Rad fans everything is so quiet I can barely hear anything.
I don't even need to run ECO now since the heat is controllable and consequently noise is much lesser.
I don't really care if the chip burns 300W as long as it stays at 80 degrees max and my room stays cool and quiet without the fans/pump going crazy.

I will buy EXPO low latency kits once they become available, like 6400 CL24 or better, I hope they come out by mid of next year, since I see Samsung already talking about really fast next gen kits.
Hopefully EXPO kits and newer BIOS will cut that memory training by a good amount, because the POST times are way too long at the moment.

 

[Markfw]

The most annoying part for me about Ryzen 7000/X670E/AM5 are the long POST times, I get boot code 15 for almost 18 seconds before OS starts to load. I hope it is just something to do with my kit being XMP.

My 1700X was a mess with memory stability but at least it ran cool even with a Noctua Low profile NH-L9x65 Air Cooler. Very quiet. And compiling code on Zen1 cause the compiler to crash when using a lot of threads, was a known problem for a while.
My 3900X has temp spikes which I hate a lot and the AM4 B550 AGESA has no option to throttle the peak temperature because a small boost is enough to send the AIO pump and fans crazy. Memory support was flaky but it got to 3200CL14
Things were very improved on 5950X and X570, the BIOS is quite mature, memory speed and stability is top notch, but not having the possibility to control spikes still irked me a lot. Temps and fans/pumps whirring bothered me.
On top of that I tried Noctua Low noise padded fans and Corsair PWM Maglev Rad fans.
Because of all of these, I operate these chips in ECO mode.

On my X670E, once I set the Tjmax to 80, everything is so quiet and cool. This is the best Ryzen chip for me.
With Corsair Maglev PWM Case and Rad fans everything is so quiet I can barely hear anything.
I don't even need to run ECO now since the heat is controllable and consequently noise is much lesser.
I don't really care if the chip burns 300W as long as it stays at 80 degrees max and my room stays cool and quiet without the fans/pump going crazy.

I will buy EXPO low latency kits once they become available, like 6400 CL24 or better, I hope they come out by mid of next year, since I see Samsung already talking about really fast next gen kits.
Hopefully EXPO kits and newer BIOS will cut that memory training by a good amount, because the POST times are way too long at the moment.

I agree with all of that, in spades. BUT, since I rarely boot my boxes, I can live with the long boot times if thats the worst of Zen4.

 

[In2Photos]

Did you try one? Let me tell you: it is not a pleasant out-of-the-box experience compared to last generation.

I plan to build my AM5 system closer to Christmas when more boards and memory kits are available. None of the reviews I watched or read said the experience was bad, only different in that the chip was built to run at 95C. So what was so bad compared to last gen?

 

[gdansk]

I plan to build my AM5 system closer to Christmas when more boards and memory kits are available. None of the reviews I watched or read said the experience was bad, only different in that the chip was built to run at 95C. So what was so bad compared to last gen?

Stock power limit is excessive. Trading ~60W for 5% less MT performance is what most people *should* do unless they have a really nice AIO. Even then you might want to tame it.
BIOS boot times are awful (Windows says my last BIOS time was 51 seconds). Some boards disable S3 sleep when EXPO or XMP is enabled.

My main gripes.
Edit: and I hope they'll fix the BIOS time and sleep settings eventually.

 

[itsmydamnation]

man you ppl go on and on about 95 like its something......

I had a X800 all in wonder , modded with X800 XT PE bios that ran at 117c full load for like 6 years.......

some people just like to create drama.

 

[In2Photos]

In DerBauer's latest video he mentions the B650E board from Gigabyte worked flawlessly for a test on the 7950x. Around 9:30. He specifically mentioned EXPO and normal boot times.

 

[Saylick]

Saw this on Twitter. Someone tested the performance of the 7950X vs. the 12900K at various power levels across multiple applications. Two observations: 1) AMD really could've backed off the power by 30%+ and they wouldn't lose more than 5-10% performance, and 2) Zen 4 on N5 really stands out in perf/W.

I highly recommend checking this blog post out. There's a ton of insight that can be gleamed for y'all Zen 4 builders out there who really want to optimize the PPT.

Ryzen 9 7950XでのPPT調整

Ryzen 9 7950Xでは、大幅に動作クロックを向上させ、PPTを定格で230Wに設定されていて、「95℃まで全力でぶん回す」仕様のCPUとなっている。 実際、自分の環境では冷却性能の限界で200W程度までしかPPT枠を使えていなくて、PPTよりも温度制限95℃が事実上のリミッターになっている。 では、PPTを下げていった場合に、どのように性能が変化するのかチェックした。 また、一部のテストを細かく見ていき、実際のCPUコア部分の...

rigaya34589.blog.fc2.com

 

[leoneazzurro]

Maybe I'm wrong, but I still expect budget boards to appear eventually that don't support 170W TDP. In those boards the chips should be set accordingly lower by default.

Custom boards made for all-in-ones/SFF PC, sure.
General purpose publicly available mainboards for DIY builds? No chance, they have to comply with AMD's guidelines.

 

[moinmoin]

The most annoying part for me about Ryzen 7000/X670E/AM5 are the long POST times, I get boot code 15 for almost 18 seconds before OS starts to load. I hope it is just something to do with my kit being XMP.

Wait. On AM4 long POST times were somewhat common for training memory, but those were mostly a one time thing. You say these long POST times happen every time? That's sure something AMD needs to improve on then...

Custom boards made for all-in-ones/SFF PC, sure.
General purpose publicly available mainboards for DIY builds? No chance, they have to comply with AMD's guidelines.

Having to be able to handle 230W PPT no matter what is in the guidelines, you sure? If so AM5 suddenly got a lot less enticing. Why should I get such an overbuild board if I plan to use it only at let's say 88W PPT.

 

[ryanjagtap]

Having to be able to handle 230W PPT no matter what is in the guidelines, you sure? If so AM5 suddenly got a lot less enticing. Why should I get such an overbuild board if I plan to use it only at let's say 88W PPT.

Maybe AMD is doing this by keeping longevity in mind. If the power budget allocation is imposed early on, they can use the same power budget in later CPUs with higher core count, and there won't be much of power constraints on the hypothetical 24/32 core zen 5 parts they will release on the AM5 platform