My plans on trying AMDs new Epyc processors for my new workstation are in their final stage. But a few questions remain.
1) Memory compatibility - frequency
Right now I can't really afford buying 16x16GB DDR4-2666 memory. But I have enough 16GB DDR4-2133 reg ECC waiting to be put to use. I know that slow memory will negatively affect performance of Epyc in general and for my applications in particular, but until memory prices drop significantly this is the only option for me.
So I contacted Supermicro just to make sure. Their support person tried to tell me that Epyc only supports DDR4-2400/2666, implying that their motherboards would not even post with DDR4-2133. I would normally call BS on that, but since this will be my first AMD setup in years I am now slightly concerned.
Any experience on that?
2) Memory compatibility - organization
I read some comments that even with 1DPC RDIMM dual-rank, maximum memory speed drops to DDR4-2133 anyway. Is that true? And what about performance? For the Desktop Ryzen processors, dual-rank DIMMs provide slightly better performance than single-rank DIMMs with the same transfer rate. Is the same true for Epyc?
3) Memory tweaking
A few of the dual-socket workstation boards for Intel that I had in the past allowed increasing memory frequency beyond the specifications of the memory. I know for a fact that the DDR4-2133 modules I have are capable of running at DDR4-2666. Any chance that there will be a dual-socket workstation motherboard for Epyc processors that allows adjusting memory frequency?
4) CPU turbo frequency
While the base clock speeds are rather low, all-core turbo frequencies listed in AMDs data sheets are pretty decent. For example 2.7GHz for the Epyc 7301. Is this a long-term turbo speed that the processor can sustain over long periods of time provided adequate cooling or is this just for a few seconds?
1) Memory compatibility - frequency
Right now I can't really afford buying 16x16GB DDR4-2666 memory. But I have enough 16GB DDR4-2133 reg ECC waiting to be put to use. I know that slow memory will negatively affect performance of Epyc in general and for my applications in particular, but until memory prices drop significantly this is the only option for me.
So I contacted Supermicro just to make sure. Their support person tried to tell me that Epyc only supports DDR4-2400/2666, implying that their motherboards would not even post with DDR4-2133. I would normally call BS on that, but since this will be my first AMD setup in years I am now slightly concerned.
Any experience on that?
2) Memory compatibility - organization
I read some comments that even with 1DPC RDIMM dual-rank, maximum memory speed drops to DDR4-2133 anyway. Is that true? And what about performance? For the Desktop Ryzen processors, dual-rank DIMMs provide slightly better performance than single-rank DIMMs with the same transfer rate. Is the same true for Epyc?
3) Memory tweaking
A few of the dual-socket workstation boards for Intel that I had in the past allowed increasing memory frequency beyond the specifications of the memory. I know for a fact that the DDR4-2133 modules I have are capable of running at DDR4-2666. Any chance that there will be a dual-socket workstation motherboard for Epyc processors that allows adjusting memory frequency?
4) CPU turbo frequency
While the base clock speeds are rather low, all-core turbo frequencies listed in AMDs data sheets are pretty decent. For example 2.7GHz for the Epyc 7301. Is this a long-term turbo speed that the processor can sustain over long periods of time provided adequate cooling or is this just for a few seconds?