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Architectures

Elja systems use x86-64 CPUs from two vendors:

  • Intel
  • AMD

Both Intel and AMD processors implement the same x86-64 (CISC) instruction set, meaning most software runs unmodified on either platform. Internally, modern CPUs from both vendors translate x86 instructions into RISC-like micro-operations, but this is an implementation detail and not visible to software.

Despite sharing an instruction set, Intel and AMD CPUs differ in their microarchitectures, instruction scheduling, cache behavior, and supported extensions. Because of this, some software is built or optimized specifically for AMD processors.

Partitions​

Intel​

Most partitions on Elja are Intel based and can use all available module trees except for libsci-amd.

AMD​

There are a total of 5 AMD based partitions. These are as follows:

  • 4x 128cpu_256mem
    • Which sport AMD EPYC 7713
  • 1x gpu-8xA100
    • Which sports AMD EPYC 7742 and a total of 8 NVIDIA A100 Tesla GPUs

Known software​

Here we will list software that is known to need a different build depending on CPU architecture:

  • Python

If you run into problems running software on these nodes and receive errors like the following, please contact irei@hi.is and let us know:

Illegal Instruction (core dumped)