It was the programmer Yuri (1usmus) who made the discovery while working on the new Clock Tuner for Ryzen (CTR) 2.0 for AMD Zen 3 CPUs. This indicates that even when it is read, there is a different table for monitoring that contains twice as many entries for these CPUs as those with a single CCD, so everything indicates that they have another one that is disabled.
Processors with “asleep” CCDs
For example, Yuri could see that CCD 1, although unavailable for processor operation, was not really completely off but just idle. In addition to the power, which was active, the CCD was in the so-called deep sleep mode which of course is a de facto shutdown (which also makes sense). However, sporadic “drawings of life” are recorded from time to time as the monitoring clock increased to 550 MHz.
We suspect that this processor is a Ryzen 9 that was returned after testing, and indeed the Ryzen 5 5600X shown here suggests a faulty Ryzen 9 5900X that may not have passed quality tests. This is not a bad thing in itself, because the demand for Ryzen CPUs is currently extremely high; however, it is suspected that the overclocking margins may be slightly lower. However, the presence of a deactivated second CCD will not affect normal operation, we can be sure of that.
We have already seen similar situations in the past: in short, we could be talking about AMD Ryzen 9 processors that did not pass AMD quality checks and whose chip was reused for a Ryzen 5, with this additional CCD disabled in some way so that the processor behaves like a Ryzen 5 when it was actually a partially faulty Ryzen 9.
Can these CCDs be activated? What Ryzen CPUs have them?
In principle it should be possible to find a way to activate both CCDs and cancel this factory-disabled area. However, this raises a question of effort and, above all, it would be advisable to know the reasons for the deactivation because even if you can activate it, it might not work as it should. Keep in mind that AMD will hardly “degrade” the margin between the Ryzen 9 and Ryzen 5, and between these and the Ryzen 7 without good reason, but you also have to remember those three cores of the Athlon II X3 processors and AMD’s Phenom II X3, where the fourth core disabled it could often be re-enabled through the BIOS without any problem.
For now, programmers continue to work with CTR 2.0 and these processors to evaluate whether or not it is possible to activate this CCD, and they assure that at the beginning of February they will be able to know whether or not it is possible. It would undoubtedly be excellent news, can you imagine buying a Ryzen 5 processor that with an update of its micro code can be mutated to a Ryzen 9?