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Why would two chiplets have any advantage over 1 chiplet?
Maybe cooling and possibly L3 cache if its not disabled.
If I had to guess as these are chiplet based chips. The 3700 has one chiplet with 8 cores.... and as its only powering one its a 65w part. While the 3800 is 2 chiplets with 4 cores each.
I could be wrong...
That's a virtual certainty.
It's just like 2700 vs 2700x. The top part is max clock speed part.
Auto-overclocking for those who don't want to bother overclocking.
Why would two chiplets have any advantage over 1 chiplet?
So you believe that a 200mhz difference requires almost twice as much power ? Perhaps. Hope launch day brings a few decent reviews.
Unknown right now. Could be an advantage. Could be a disadvantage as well... as I don't believe chiplets can share cache with each other. Its possible if the 3700 is actually just one chiplet it has the advantage. Or there could be none. We need a good [H] type review.
IMO, back when Ryzen launched, there was little reason to get the 1800x over the 1700x.
To me, the 3800x feels somewhat strange on the product stack, given where the 3700x is.
https://hardforum.com/threads/ryzen-3000-ccx-and-core-layout.1982784/#post-1044229047If I had to guess as these are chiplet based chips. The 3700 has one chiplet with 8 cores.... and as its only powering one its a 65w part. While the 3800 is 2 chiplets with 4 cores each.
I could be wrong... but that is all I could think of as to why there is such a drastic power difference. Seems logical they would be able to squeeze a few more MHZ out of the part where they can basically disable the weakest cores.
I am looking at both but will be waiting for a few good in depth reviews. The extra power draw might be worth it... or not.
the L3 would be the big difference, I feel. But based on specs either AMD is lopping off the L3 of the 2nd chiplet, or just going with a single die. the 12 core is the big L3 bump per their specs.
Don't they say that the lower tdp parts are worse when run at the higher frequencies? I.e. they leak more, so they limit their vcore to where their efficiency falls in line?
According to AMD, the L2 (4MB) and L3 (32MB) cache for the 3700x and 3800x are the same.
https://www.amd.com/en/products/cpu/amd-ryzen-7-3700x
https://www.amd.com/en/products/cpu/amd-ryzen-7-3800x
So the only difference is the 3700x has a 300MHz lower base clock and 100MHz lower boost clock while being a 65W TDP part (3800X is 105W TDP).
You can't even argue the 3800x is better binned because the 3700x has a much lower TDP. I mean, it seems to me the 3700x is better binned.
In some ways, I expect the 3800X to actually be inferior ( like for instance with efficiency at lower clockspeeds). Just like the 2700 vs 2700X.
Where is there any evidence of this?
The_Stilt discusses it here: https://forums.anandtech.com/threads/ryzen-strictly-technical.2500572/page-72
The money quote regarding leakage/power consumption:
"Because of that, the 2700X SKUs most likely uses silicon which features higher SIDD (static leakage) than the average silicon used in other lower clocked SKUs. Silicon which features higher SIDD will most of the time require less voltage to reach certain frequency, compared to silicon with lower leakage characteristics. However, despite the lower voltage on the higher SIDD silicon, the power consumption is usually slightly higher due to the higher current draw and temperatures (and therefore lower overall efficiency)."
Translation: some silicon can hit higher clockspeeds at lower voltage, but that silicon tends to draw higher power (than other silicon) at lower frequencies. A 2700 won't clock as high as a 2700X at a given voltage, but it will be more efficient at lower clockspeeds. AMD can bin for this with Zen 2, as well - which is what I suspect the difference is between the 3700X and 3800X.
Seriously? Using speculation of someone on another forum as "evidence". He didn't even test a 2700, he was just guessing.
In reality, typically the higher binned parts, tend to run higher clocks at lower voltage and less power, those same parts tend to exhibit that same behavior when clocked lower, IOW they are better everywhere.
What I think both of you are confusing, is when you have a specific "low power process(LPP)", that uses less power at lower frequencies than the "high power process(HPP)". But LPP falls apart at higher clock speeds. Likewise HPP tends to be inefficient at lower clock speeds.
But this doesn't translate to binned parts in the same process, top binned parts just tend to be "best of" process examples and are better everywhere.
3700X = 2700. A lower clocked part, clamped to a lower power. If you manually overclock they would be about the same as their higher clocked counterpart, but then lacking the features that reduce clocks and power under lighter loads.
Just like for 2700/2700X, with 3700X/3800X you get the 3700X if you want to manually overclock, though you will end up using more power (require more cooling) than what the 3800X will give you automatically.
Reading comprehension, mang. This is regarding CPUs on the same process, so it's not a confusion of LPP vs HPP.
He did test the 1700 vs the 1800X earlier in that thread, and those had the characteristics he described. He also tested earlier Bulldozer binnings and those had the characteristics too. He says that in the link I sent you. AMD has a history of binning this way. He extrapolated re: 2700 vs 2700X. The Stilt has a history of being right on these things, too. He wrote the book on Ryzen memory timings and speeds. In an earlier thread you accused me of claiming I was an expert. I wasn't, and am not. But The Stilt is.
The part with lower SIDD will not clock as high (unless you give it extra voltage vs. the part with higher SIDD), but will be more efficient at lower clocks. It's not really a hard concept to grasp. Binning is more complicated than just "this one is better in all the things."
This is guessing based on a belief that the same process work like the difference between LPP and HPP.
Testing one or two samples says nothing. Especially 1700 vs 1800x. Anyone paying attention in those days knows there wasn't much binning at all. 1700 often over-clocked higher than 1800x. It was very much a silicon lottery.
Evidence would require a demonstrated consistent pattern, and guessing based on the result testing a couple of 1700/1800x parts is laughable.
You are confusing "proof" with "evidence". One sample is evidence, albeit not necessarily very convincing evidence. One sample is not proof. As it so happens, he tested a few Ryzen CPUs, and also a few Bulldozer CPUs, and noticed the same pattern in all of his samples..
Then show that actual information. One sample is weak evidence at best.
But you didn't even provide that. You provided a link to speculation, not the actual weak "evidence".
It's all in that thread. He dissects Zen's characteristics pretty thoroughly there, and has charts/data for all of his various tests, including the power curves. Read it, or don't.
You demand that I adhere to a standard of evidence you yourself aren't willing to provide for your own assertions, and then don't even want to read what I link you to. ¯\_(ツ)_/¯
Gee, why wouldn't I want to read 2000+ post haystack in search of needle of thin evidence?
If you ever actually find the appropriate post, I will be happy to read it.
The_Stilt discusses it here: https://forums.anandtech.com/threads/ryzen-strictly-technical.2500572/page-72
The money quote regarding leakage/power consumption:
"Because of that, the 2700X SKUs most likely uses silicon which features higher SIDD (static leakage) than the average silicon used in other lower clocked SKUs. Silicon which features higher SIDD will most of the time require less voltage to reach certain frequency, compared to silicon with lower leakage characteristics. However, despite the lower voltage on the higher SIDD silicon, the power consumption is usually slightly higher due to the higher current draw and temperatures (and therefore lower overall efficiency)."
Translation: some silicon can hit higher clockspeeds at lower voltage, but that silicon tends to draw higher power (than other silicon) at lower frequencies. A 2700 won't clock as high as a 2700X at a given voltage, but it will be more efficient at lower clockspeeds. AMD can bin for this with Zen 2, as well - which is what I suspect the difference is between the 3700X and 3800X.
So going by hwbot's numbers, the 2700x's average air overclock is about 220 MHz more than the 2700 which is about the same as the 1700 vs 1800x.
Below chart indicates that 1700 is *worse* at efficiency than the 1800x at the same clock speeds (unless I'm reading it wrong). Of course that's limited samples.
https://forums.anandtech.com/threads/ryzen-strictly-technical.2500572/page-73
Filter by "The Stilt". Everything else in that thread is just noise/comments. I found you the original I was referencing when you asked for it, if you want more, I'm not your personal search engine. But it's in there.
Also if you want to read more on the concept he is referencing, you can familiarize yourself with static leakage here: http://www.ruf.rice.edu/~mobile/elec518/readings/DevicesAndCircuits/kim03leakage.pdf
It's been a big problem for a while now and continues to get more difficult to manage with smaller nodes.
I know about static leakage, it was a huge issue around 28nm transition until FinFets were used to mitigate to tolerable levels.
But nothing says that a processor on the same process, that uses less power at high frequency (when compared to another) would reverse that trend at low power.
Top binned parts, tend to be winners in the silicon lottery that run at lower voltage across the board.
So if you want to compare power at lower speed, both parts should be set to their minimum stable voltage for that clock speed, which should be lower for the better binned part, which should equate lower power. Lower supply voltage leads to lower static power leakage, and lower operating power.