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?

If you sniff & lick another man's ass like Joel does,
all the cores will be present.

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.

Paul

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-9-3900xt-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 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.

Paul

On Fri, 28 Apr 2023 06:16:12 +0100, captain_penis <vagina_stench@aol.com> 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-9-3900xt-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.

Why would I sniff a 4 legged animal?

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-9-3900xt-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.

Why can it not be sold as a 8c/16t CPU?

On Fri, 28 Apr 2023 10:46:19 +0100, Paul <nospam@needed.invalid> wrote:

> 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.

I remember something about a 386 or 486 where you could turn the DX arithmetic thing on with a jumper on the motherboard. Not sure how Intel got away with that. Surely everyone would buy the SX chip cheaper then move the jumper.

> 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.

I would have sold them as they were, but adjusted the pricing on the fly to meet demand.

> 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.

I read something about it's able to disable it's own cores if one fails later?

On 4/29/2023 1:34 PM, Commander Kinsey wrote:
> 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-9-3900xt-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.
>
> 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.

Paul

On Sat, 29 Apr 2023 19:02:07 +0100, Paul <nospam@needed.invalid> wrote:

> On 4/29/2023 1:34 PM, Commander Kinsey wrote:
>> 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-9-3900xt-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.
>>
>> Why can it not be sold as a 8c/16t CPU?
>
> If you fail on an IDDD test, the chiplet is immediately junk.

I meant why can't it be sold as a CPU with a chiplet missing?

> 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.

5 volts 1 ohm? 5W. Wouldn't that quickly melt the chip?

> So it would go with a bad chiplet being stuffed in a package.
> It could potentially be a waste of electricity.

I'm not a treehugger.