Re:AMD Ryzen 7000 Burning Out: Impacts all 7000 processors
by Dalewyn on Thursday April 27, 2023 @02:05AM
(#35723869)
I'll leave my little anecdata with Intel Alder Lake memory controller shenanigans since it's relevant.
I built an i7 12700K system last year with 4x16GB DIMMs of DDR5-5600 RAM, for a total of 64GB RAM. Not being fully aware of the memory controller's limitations at that point (moral: read the datasheets!) I turned on XMP which naturally overclocked the RAM to 5600MHz. Note that at this point I was curious why the mobo had booted the system with RAM clocked to 4000MHz prior to my fiddling around with the BIOS.
Not long after, I had instability which manifested in random program and system crashes. Eventually I checked the RAM and confirmed that was the issue with memtest86 returning errors. I read up on the CPU's datasheet and learned that when supplied with 2 DIMMs per channel with 1 rank per DIMM, the memory controller downclocks to 4000MHz as specified. Incidentally, this answered why the mobo booted the system up with RAM clocked to 4000MHz at the beginning.
I turned off XMP and backed off the overclock to 4800MHz with timings as applied by the mobo (they're just JEDEC profile timings), and that got me back to stability with subsequent tests in memtest86 returning no errors.
The important things to takeaway here are that:
* DDR5 memory controllers are still in their infancy compared to DDR4 and DDR3 controllers today, and can't yet deal with so much RAM at once.
* Going beyond 1 DIMM per channel, 1 rank per DIMM means the memory controller will run slower than advertised, and this is according to specification. It is on us the end-users to do our homework, we can't forget we are using precision electronics.
* With the memory controller running slower, overclocks are that much more taxing than XMP/EXPO and the marketing would imply. Simply turning on XMP/EXPO without thought is dangerous because those profiles do not account for a slower memory controller.
* Overclocking is by its very definition running hardware above and beyond what they were designed and rated to operate at. Warranties will be voided, and hardware can be damaged or destroyed because they are operated out of specification. You have been warned, ignorance is not an excuse.
* Between CPUs (and GPUs) today coming "over"clocked from the factory to perform at their peak and RAM speed having negligible real world performance implications for the vast majority of use cases, end-user overclocking is simply not worth the hassle unless you absolutely know what you're doing.
* EFI/BIOS firmware nearly always come out of the box with safe defaults. If you don't know what you're doing, leaving them alone is perfectly fine. You will still have a very performant system. Overclocking is not for the faint of heart (nor the ignorant!).
I built an i7 12700K system last year with 4x16GB DIMMs of DDR5-5600 RAM, for a total of 64GB RAM. Not being fully aware of the memory controller's limitations at that point (moral: read the datasheets!) I turned on XMP which naturally overclocked the RAM to 5600MHz. Note that at this point I was curious why the mobo had booted the system with RAM clocked to 4000MHz prior to my fiddling around with the BIOS.
Not long after, I had instability which manifested in random program and system crashes. Eventually I checked the RAM and confirmed that was the issue with memtest86 returning errors. I read up on the CPU's datasheet and learned that when supplied with 2 DIMMs per channel with 1 rank per DIMM, the memory controller downclocks to 4000MHz as specified. Incidentally, this answered why the mobo booted the system up with RAM clocked to 4000MHz at the beginning.
I turned off XMP and backed off the overclock to 4800MHz with timings as applied by the mobo (they're just JEDEC profile timings), and that got me back to stability with subsequent tests in memtest86 returning no errors.
The important things to takeaway here are that:
* DDR5 memory controllers are still in their infancy compared to DDR4 and DDR3 controllers today, and can't yet deal with so much RAM at once.
* Going beyond 1 DIMM per channel, 1 rank per DIMM means the memory controller will run slower than advertised, and this is according to specification. It is on us the end-users to do our homework, we can't forget we are using precision electronics.
* With the memory controller running slower, overclocks are that much more taxing than XMP/EXPO and the marketing would imply. Simply turning on XMP/EXPO without thought is dangerous because those profiles do not account for a slower memory controller.
* Overclocking is by its very definition running hardware above and beyond what they were designed and rated to operate at. Warranties will be voided, and hardware can be damaged or destroyed because they are operated out of specification. You have been warned, ignorance is not an excuse.
* Between CPUs (and GPUs) today coming "over"clocked from the factory to perform at their peak and RAM speed having negligible real world performance implications for the vast majority of use cases, end-user overclocking is simply not worth the hassle unless you absolutely know what you're doing.
* EFI/BIOS firmware nearly always come out of the box with safe defaults. If you don't know what you're doing, leaving them alone is perfectly fine. You will still have a very performant system. Overclocking is not for the faint of heart (nor the ignorant!).