I came across "The Ryzen 9 3900XT has 2 CCDs with each 2 CCXs. Each CCX has 1 out of the 4 cores disabled. Adding up all the cores that are left, 3 times 4, makes 12 cores" on https://skatterbencher.com/2020/07/07/skatterbencher-13-amd-ryzen-9-3900xt-overclocked-to-4550-mhz/
What's that? DISABLED?! I've got a 16 core CPU here with 4 turned off? Why are they off? Can I turn them on?
I came across "The Ryzen 9 3900XT has 2 CCDs with each 2 CCXs. Each CCX
has 1 out of the 4 cores disabled. Adding up all the cores that are
left, 3 times 4, makes 12 cores" on https://skatterbencher.com/2020/07/07/skatterbencher-13-amd-ryzen-9-3900xt-overclocked-to-4550-mhz/
What's that? DISABLED?! I've got a 16 core CPU here with 4 turned off?
Why are they off? Can I turn them on?
On 4/28/2023 12:27 AM, Commander Kinsey wrote:
I came across "The Ryzen 9 3900XT has 2 CCDs with each 2 CCXs. Each CCX
has 1 out of the 4 cores disabled. Adding up all the cores that are
left, 3 times 4, makes 12 cores" on
https://skatterbencher.com/2020/07/07/skatterbencher-13-amd-ryzen-9-3900xt-overclocked-to-4550-mhz/
What's that? DISABLED?! I've got a 16 core CPU here with 4 turned off?
Why are they off? Can I turn them on?
https://www.guru3d.com/articles-pages/amd-ryzen-9-3900xt-review,2.html
Ryzen 9 3950X (16c/32t) will be priced 749 USD
Ryzen 9 3900X (12c/24t) will be priced 499 USD <===
If there is any defect (functional fault or "speed" fault),
it is "gimp-by-4". And this is the "resolution" of the SKUs for sale.
This means they sell the defective silicon, to improve the yield.
The defective silicon is not in your critical path, because
it's been pinned off.
Some single flaws in a chiplet, cause the entire chiplet to fail.
A pinning strategy cannot work for that case. This means some
of the chiplets are still getting thrown away. But for certain
classes of faults, they can make intelligent usage of the chiplet.
And make a 12 core CPU with it.
Your expensive processor, is an IO chip and two CPU chiplets.
if all the silicon is perfect, they charge 749 USB for that.
At the binning machine, there would be a bigger pile of 12 core
chips, than of 16 core chips.
*******
Entirely different than my cheap 6C/12T processor, which is a *single die*. That means mine is a traditional design.
https://www.techpowerup.com/285534/amd-ryzen-5-5600g-apu-die-shots-published
You see the beauty trick they pulled in there ? There are 7 cores,
they pin one off on all the chips, and that makes a 6 core 12 thread CPU.
So the slowest core gets chucked, you get to keep the better ones.
If the ALU in a single core was defective, they would still sell
the chip to me, by pinning off that core.
https://www.techpowerup.com/img/Cx4d2xiOUBzlnMX4.jpg
*******
Because your compute complex relies on a fabric, physical
monitors, a characterization table, if you were to turn
on the defective cores, the characterization table won't
have data in the table for the defective cores. Crash-ola,
could be the end result. Depending on the flavour of turbo
mine has got, even my cheap CPU could have a characterization
table, for picking where to run the "single thread" case.
Yep. This is nothing new. AMD have been doing for decades since the Athlon
to increase how many dies they can sell.
Yes they're disabled but it doesn't mean they are working cores. In the
early days you could enable them with a pencil mark, with limited success.
On 4/28/2023 12:27 AM, Commander Kinsey wrote:overclocked-to-4550-mhz/
I came across "The Ryzen 9 3900XT has 2 CCDs with each 2 CCXs. Each CCX has 1 out of the 4 cores disabled. Adding up all the cores that are left, 3 times 4, makes 12 cores" on https://skatterbencher.com/2020/07/07/skatterbencher-13-amd-ryzen-9-3900xt-
What's that? DISABLED?! I've got a 16 core CPU here with 4 turned off? Why are they off? Can I turn them on?
https://www.guru3d.com/articles-pages/amd-ryzen-9-3900xt-review,2.html
Ryzen 9 3950X (16c/32t) will be priced 749 USD
Ryzen 9 3900X (12c/24t) will be priced 499 USD <===
If there is any defect (functional fault or "speed" fault),
it is "gimp-by-4". And this is the "resolution" of the SKUs for sale.
This means they sell the defective silicon, to improve the yield.
The defective silicon is not in your critical path, because
it's been pinned off.
Some single flaws in a chiplet, cause the entire chiplet to fail.
A pinning strategy cannot work for that case.
On 4/28/2023 12:27 AM, Commander Kinsey wrote:
I came across "The Ryzen 9 3900XT has 2 CCDs with each 2 CCXs. Each CCX
has 1 out of the 4 cores disabled. Adding up all the cores that are
left, 3 times 4, makes 12 cores" on
https://skatterbencher.com/2020/07/07/skatterbencher-13-amd-ryzen-9-3900xt-overclocked-to-4550-mhz/
What's that? DISABLED?! I've got a 16 core CPU here with 4 turned off?
Why are they off? Can I turn them on?
If you sniff & lick another man's ass like Joel does,
all the cores will be present.
On 4/28/2023 3:45 AM, Chris wrote:
Yep. This is nothing new. AMD have been doing for decades since the Athlon >> to increase how many dies they can sell.
Yes they're disabled but it doesn't mean they are working cores. In the
early days you could enable them with a pencil mark, with limited success.
There was a time, when CPU design was a lot simpler.
Changing a three core chip to a four core chip,
was a simple go-nogo test.
It could be the fourth
core was thrown away (because the four core chips
were yielding so well, and they could not satisfy
the market demand for the "cheaper priced" three core
ones). Enabling a perfectly good core in that case,
was a slam dunk.
the current designs are way too complicated, for that
simple outcome. You don't really know what fault-flavour
is in there when the thing crashes on you.
On Fri, 28 Apr 2023 06:58:38 +0100, Paul <nospam@needed.invalid> wrote:overclocked-to-4550-mhz/
On 4/28/2023 12:27 AM, Commander Kinsey wrote:
I came across "The Ryzen 9 3900XT has 2 CCDs with each 2 CCXs. Each CCX has 1 out of the 4 cores disabled. Adding up all the cores that are left, 3 times 4, makes 12 cores" on https://skatterbencher.com/2020/07/07/skatterbencher-13-amd-ryzen-9-3900xt-
What's that? DISABLED?! I've got a 16 core CPU here with 4 turned off? Why are they off? Can I turn them on?
https://www.guru3d.com/articles-pages/amd-ryzen-9-3900xt-review,2.html
Ryzen 9 3950X (16c/32t) will be priced 749 USD
Ryzen 9 3900X (12c/24t) will be priced 499 USD <===
If there is any defect (functional fault or "speed" fault),
it is "gimp-by-4". And this is the "resolution" of the SKUs for sale.
This means they sell the defective silicon, to improve the yield.
The defective silicon is not in your critical path, because
it's been pinned off.
Some single flaws in a chiplet, cause the entire chiplet to fail.
A pinning strategy cannot work for that case.
Why can it not be sold as a 8c/16t CPU?
On 4/29/2023 1:34 PM, Commander Kinsey wrote:3900xt-overclocked-to-4550-mhz/
On Fri, 28 Apr 2023 06:58:38 +0100, Paul <nospam@needed.invalid> wrote:
On 4/28/2023 12:27 AM, Commander Kinsey wrote:
I came across "The Ryzen 9 3900XT has 2 CCDs with each 2 CCXs. Each CCX has 1 out of the 4 cores disabled. Adding up all the cores that are left, 3 times 4, makes 12 cores" on https://skatterbencher.com/2020/07/07/skatterbencher-13-amd-ryzen-9-
What's that? DISABLED?! I've got a 16 core CPU here with 4 turned off? Why are they off? Can I turn them on?
https://www.guru3d.com/articles-pages/amd-ryzen-9-3900xt-review,2.html
Ryzen 9 3950X (16c/32t) will be priced 749 USD
Ryzen 9 3900X (12c/24t) will be priced 499 USD <===
If there is any defect (functional fault or "speed" fault),
it is "gimp-by-4". And this is the "resolution" of the SKUs for sale.
This means they sell the defective silicon, to improve the yield.
The defective silicon is not in your critical path, because
it's been pinned off.
Some single flaws in a chiplet, cause the entire chiplet to fail.
A pinning strategy cannot work for that case.
Why can it not be sold as a 8c/16t CPU?
If you fail on an IDDD test, the chiplet is immediately junk.
As a hobbyist, I bought a bag of "untested 555 timers" from a supplier.
Nine of them, had a dead short between VCC and GND.
One of them, was good.
My conclusion, was they had already tested them. There was a pile of duff ones, a pile of good ones, and they would mix them in the baggy,
in the ratio of 9:1 for each customer :-)
The ohmmeter would read 1 ohm between VCC and GND, so that
would draw a fair amount of current while doing nothing, if
you insisted on using it.
So it would go with a bad chiplet being stuffed in a package.
It could potentially be a waste of electricity.
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