Question AMD Rembrandt/Zen 3+ APU Speculation and Discussion

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Abwx

Diamond Member
Apr 2, 2011
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5800U DDR4-3200 22-22-22 vs 6800U LPDDR5-6400 19-15-17 :laughing:
5800U 15W vs 6800 28W :laughing:
Zero about the Iris Xe device, probably DDR4



But it's AMD, it's fine. If Intel does this the forum explodes.
A 28W 5800U perform exactly 28% better that it does at 15W, so it s unlikely that their 5800U was ran at 15W, it would mean that RMB is also 7nm with no CPU MT perf enhancement.
 

mikk

Diamond Member
May 15, 2012
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A 28W 5800U perform exactly 28% better that it does at 15W, so it s unlikely that their 5800U was ran at 15W, it would mean that RMB is also 7nm with no CPU MT perf enhancement.

The CPU comparison is useless until we get the real power consumption, assuming 15W vs 28W wasn't. This is a really bad presentation. And of course they should have used a LPDDR4x device for 5800U, there are some Lenovo Yoga and Thinkpad devices in the market.
 

Shivansps

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Sep 11, 2013
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So in desktop, Zen4 is Ryzen 7000 and launching in H2 along with AM5, but they skipped the 6000 series that are likely reserved for RMB, i think it is safe to say desktop RMB by the end of the year, if it ever comes out.
 

Abwx

Diamond Member
Apr 2, 2011
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The CPU comparison is useless until we get the real power consumption, assuming 15W vs 28W wasn't. This is a really bad presentation. And of course they should have used a LPDDR4x device for 5800U, there are some Lenovo Yoga and Thinkpad devices in the market.
Fortunately they used Cinebench, wich is straightforward for comparison of a same or so design.

A 6nm fabbed theorical 5800U ran at 28W would be at least 40% faster in MT than a 7nm based one fed with 15W, so it s likely that the 5800U was tested at its usual 25W cTDP, still a 3W advantage for RMB but not that significant overall.
 

mikk

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May 15, 2012
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Does anyone even sell 5800u devices with DDR4-3200 CAS/CL 22?

Yes there are a lot of DDR4 devices and CL22 is standard for DDR4-3200 sodimm. The odd part is 19-15-17 on LPDDR5-6400, how is this even possible? Maybe it's doubled and it's CL38 in real. AMD really failed on this.
 

insertcarehere

Senior member
Jan 17, 2013
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Fortunately they used Cinebench, wich is straightforward for comparison of a same or so design.
AMD's footnotes here literally says:
Based on testing by AMD as of 12/14/2021. CPU performance evaluated with a geomean of 9 multi-threaded content creation and CPU tests.
That's not "just Cinebench".

Frankly, the greater concern is the 6800u Laptop's use of very aggressive LPDDR5 modules, which is 99% not going to translate to laptop OEMs, and thus put a damper to claimed gpu gains.
 
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Abwx

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eek2121

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Aug 2, 2005
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The CPU comparison is useless until we get the real power consumption, assuming 15W vs 28W wasn't. This is a really bad presentation. And of course they should have used a LPDDR4x device for 5800U, there are some Lenovo Yoga and Thinkpad devices in the market.
So maybe you are confused about cTDP.

The 5800U had a 10-25W cTDP: AMD Ryzen™ 7 5800U | AMD
The 6800U has a cTDP of 15-28W: AMD Ryzen™ 7 6800U | AMD
 

DrMrLordX

Lifer
Apr 27, 2000
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Yes there are a lot of DDR4 devices and CL22 is standard for DDR4-3200 sodimm.
Interesting. I thought CL20 was the typical JEDEC standard used by OEM machines. Maybe that's more for standard DIMMs. The LPDDR5 timings are odd. Surely something isn't right there.
 

Abwx

Diamond Member
Apr 2, 2011
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If they compared 5800U 15W vs 6800U 28W then the increase in Cinebench is not surprising. If It was 25W vs 28W then there would be barely any difference.

R7 5800U at 25W is 24% faster than at 15W.
You forgot that RMB is 6nm fabbed; so i guess that you re saying that this node didnt bring any perf/Watt improvement, as well as AMD engineers being so lazy that they didnt even bother to improve the design.
 

insertcarehere

Senior member
Jan 17, 2013
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I think the one big thing nobody is spaeaking about is not performance, but battery life. Now, 24h is certainly not the average result, but the comparisons with 5800U in workloads are quite good fir such a powerful APU.
That's because the battery claims aren't test results, but projections from AMD themselves:

Engineering projections are not a guarantee of final performance. Performance projection by AMD engineering staff based on expected battery life for idle, video playback, modern standby, and esports gaming vs. Ryzen 5000 series mobile processors with the same TDP. Power reduction projections based on pre-silicon engineering analysis . Estimated battery life increases assume identically HW & SW configured systems. Specific projections are based on reference design platforms and are subject to change when final products are released in market. RMB-3
 

Abwx

Diamond Member
Apr 2, 2011
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That's why nVidia did the mx570 and 2050L.
Are you sure that it s not rather because of this :

 

jpiniero

Lifer
Oct 1, 2010
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Are you sure that it s not rather because of this :

I suppose the 2050L could be a response to Navi 24.
 

insertcarehere

Senior member
Jan 17, 2013
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Projections based on their internal testing with preproducion silicon and identical configurations, of course they cannot guarantee for an OEM.
Again, the footnotes from AMD themselves say:
Performance projection by AMD engineering staff based on expected battery life for idle, video playback, modern standby, and esports gaming vs. Ryzen 5000 series mobile processors with the same TDP. Power reduction projections based on pre-silicon engineering analysis.
How does the above somehow translate into internal testing with actual silicon? Especially when the performance footnotes with testing are significantly more specific.
 
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TESKATLIPOKA

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May 1, 2020
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You forgot that RMB is 6nm fabbed; so i guess that you re saying that this node didnt bring any perf/Watt improvement, as well as AMD engineers being so lazy that they didnt even bother to improve the design.
So you are saying that HP ProBook 635 Aero G8 with R7 5800U was actually set to 25W even though they stated in footnotes:
Based on testing by AMD as of 12/14/2021. CPU performance evaluated with a geomean of 9 multi-threaded content creation and CPU tests. GPU performance evaluated with 3DMark® Time Spy. System configuration for Ryzen™ 7 5800U CPU/GPU performance: HP ProBook 635 Aero G8 configured with 2x8GB DDR4-3200 (22-22-22), Windows® 11 22000.282, Samsung 980 Pro 1TB SSD, 15W nominal processor TDP, GPU driver 27.20.21026, BIOS T83. System configuration for Ryzen™ 7 6800U CPU/GPU performance: AMD reference motherboard configured with 4x4GB LPDDR5-6400 (19-15-17), Windows® 11 22000.282, Samsung 980 Pro 1TB SSD, 28W nominal processor TDP, GPU driver 30.0, BIOS TRM0081D. RMB-13
that It was only at 15W, right?
OK, so where is your proof? I guess It was just too much of a bother searching for It.

Unlike you, I found a review of HP ProBook 635 Aero G8 with R7 5800U and yes, the score in CB R23 is 9576 points, which would mean It was set to 25W.
Now the question is If they have a typo in their footnotes or they manually set TDP to 15W.
 
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