https://gmplib.org/gmp-zen5
连结内有一些CPU的图跟两台的配备
全部贴来PTT好像有点长，我截下面比较重要的部分+AI翻
We really don’t know what is wrong here. Let us list some observations and
thoughts:
The ambient temperature was in both cases quite low.
These are supposedly top-quality motherboard (We’ve had about 50 ASUS
motherboard over the years, and only had one failure).
The offset mounting does not look right to us. But this is how things are
supposed to be done.
It is possible that we caused the 2nd CPU failure by inadequate mounting of
the heat sink. It surely seems bizarre to have the thermal paste squeezed like
shown on the pictures above!
But note that the 1st failure happened with a more centred heat sink. We only
made the off-centre mounting for the 2nd system as to minimise the risk of a
repeated system failure.
The so-called TDP of the Ryzen 9950X is 170W. The used heat sinks are
specified to dissipate 165W, so that seems tight. We have extra fans in the
cases and a low ambient temperature, making these 5W seem negligible. But of
course, this is not completely kosher.
We have a sister system for the 9950X, a 7950X which is similarly configured
and built. That system actually seems to run slightly hotter, but it has been
stable for a long time (under the same crazy load!).
The systems were under maximal load at the time their CPUs died, running very
tight handcrafted asm loops sustaining one MULX per cycle. That might be a “
hot” instruction.
Did the CPUs die of heat stroke? Modern CPUs measure their temperature and
clock down if they get too hot, don’t they?
We don’t overclock or overvolt or play other teen games with our hardware.
The extremely thin layer of thermal paste which resulted from the off-centre
heat sink mount, might seem fine. We however suspect that there might be a
problem, as when the system heats and cools, things bend a little. With a
remaining layer of thermal paste, such bending will not create any void as the
paste’s elasticity will maintain some contact. When the thermal paste is
squeezed away as with the suggested Noctua mounting, an ever-so-slight void
between the CPU and the heat sink might be created.
Neither of the 9950X CPUs died immediately, instead they died the exact same
way after a couple of months at high load. This seems to suggest a gradual but
predictable degradation.
我们真的不清楚问题出在哪里。以下是一些我们的观察与想法：
两次故障发生时，环境温度都相当低。
我们使用的是公认品质顶尖的主机板
（多年来我们用过约 50 张 ASUS 主机板，只坏过一张）。
偏置安装看起来很奇怪，但这却是官方建议的安装方式。
第二次 CPU 故障有可能是我们安装散热器不当所致。散热膏被挤压成上图那样，确实有
点匪夷所思。
但值得注意的是，第一次故障时散热器是置中安装的。我们在第二套系统上改用偏置安装
，正是为了避免重蹈覆辙。
Ryzen 9950X 的所谓热设计功耗（TDP）是 170W，而我们使用的散热器解热能力规格为
165W，规格上确实有点吃紧。不过考量到我们在机壳内加装了风扇，且环境温度低，这
5W 的差距应该可以忽略。但严格来说，这确实不是最标准的作法。
我们有一套与 9950X 系统配置相近的 7950X 系统。那套系统的运作温度似乎还稍微高一
些，但在同样极端的负载下，它已经稳定运行了很长时间。
CPU 烧毁的当下，系统都处于满载状态，持续运行着我们手动编写、极度精简的 asm 回
圈，每个时脉周期执行一次 MULX 指令。这或许是个发热量极大的指令。
CPU 是因为过热烧毁的吗？现代 CPU 不是都有温度监控，会在过热时自动降频保护吗？
我们从不对硬件进行超频、加压或任何类似的胡乱设定。
偏置安装导致散热膏层极薄，表面上可能没问题。但我们怀疑，当系统反复升温和降温时
，金属会产生微小的形变。如果还有一层散热膏，膏体的弹性可以填补缝隙，维持接触。
但若像 Noctua 建议的安装方式那样将散热膏完全挤开，CPU 和散热器之间就可能因形变
产生一道极其微小的空隙。
两颗 9950X CPU 都不是立即损坏，而是在高强度负载几个月后，以完全相同的方式故障
。这似乎指向一种缓慢但可预测的渐进式损耗。
关于文中提到的off-centre mounting
We use a Noctua cooling solution for both systems. For the 1st system, we
mounted the heat sink centred. For the 2nd system, we followed Noctua’s
advice of mounting things offset towards what they claim to be the hotter side
of the CPU. Below is a picture of the 2nd system without the heat sink which
shows that offset. Note the brackets and their pins, those pins are where the
heat sink’s pressure gets centred. Also note how the thermal paste has been
squeezed away from that part, but is quite thick towards the left.
我们的两套系统都采用 Noctua 散热器。第一套系统，我们将散热器置中安装。到了第二
套系统，我们则遵循 Noctua 的建议，将散热器偏向他们所谓 CPU 较热的一侧进行安装
。下方是第二套系统未安装散热器的照片，可以清楚看到偏置安装的状况。请注意支架和
卡榫，散热器的压力就集中在这些卡榫上。同时也请注意，散热膏如何从压力集中处被完
全挤开，但在左侧却保留了相当的厚度。