For systems that are going to have 4GB or less of physical memory, you should absolutely make more efficient use of it by opting for a 32-bit processor, like this one:
https://www.gaisler.com/index.php/products/processors/leon5
It also makes sense to have low core count (quad core should be enough), because you're limited by the number of threads that a program can have anyways. However, make sure that you properly verify the stack size limits (and hence the available memory left for heap memory allocation), the memory usage by the OS and the size of the address space for a program. These parameters can generally be changed. According to the internet, a 32-bit Solaris SPARC kernel limits the address space to 2 GB even though a 32 bit system can have 4 GB virtual address space. So, it does make sense to pair this processor with 2 GB RAM instead of 4 GB.
https://www.oracle.com/java/technologies/hotspotfaq.html#gc_heap_32bit
https://www.oracle.com/solaris/technologies/memory.html
The company in question does have a board with LEON4FT processor, but I'd like to use LEON5 instead.
