It was reported, that SPT tasks use more memory than they advertise. Around 600MiB. This is quite a lot. What is using so much memory? If it is the sieve, then OK. But if it is wasted memory, then fix the issue.

Please write the memory usage of spt tasks on your system here. It will save me searching for the statistics in db.

Memory usage of some of my hosts:

Intel(R) Atom(TM) x5-Z8300, Win10 64bit:
Peak working set size 932.83 MB, Peak swap size 943.20 MB, https://boinc.tbrada.eu/result.php?resultid=1611243
Peak working set size 778.78 MB, Peak swap size 943.20 MB, https://boinc.tbrada.eu/result.php?resultid=1560295

Intel(R) Celeron(R) J4105, Linux Ubuntu 19.04:
Peak working set size 937.06 MB, Peak swap size 942.44 MB, https://boinc.tbrada.eu/result.php?resultid=1566533

Ryzen 7 2700, Linux Mint 18.1
Peak working set size 334.46 MB, Peak swap size 334.87 MB, https://boinc.tbrada.eu/result.php?resultid=1617927

Hardkernel ODROID-N2, Ubuntu 18.04.3 LTS
Peak working set size 613.77 MB, Peak swap size 621.27 MB, https://boinc.tbrada.eu/result.php?resultid=1575211
Peak working set size 475.45 MB, Peak swap size 621.27 MB, https://boinc.tbrada.eu/result.php?resultid=1575177

Odroid-C2, Linux 16.04
Peak working set size 612.60 MB, Peak swap size 621.28 MB, https://boinc.tbrada.eu/result.php?resultid=1559210
Peak working set size 450.38 MB, Peak swap size 621.28 MB, https://boinc.tbrada.eu/result.php?resultid=1590109

spt_104_windows_x86_64, SHA256: 351B4A9C6528BEA1CAF0A8CCDC8CF97C139A1AF706B0F6E26D5897A31E84285B

Ryzen 1700, Win7 (all 11 in parralel):
343MB private, 342MB working set

No post-Mеltdown/Spеctre mitigatiоns instаlled.
e.g. this task

The batch 50 has increased formal memory requirement, but it is a wild guess. The memory usage of the sieve is supposed to be pi(sqrt(n))*8 bytes, but idk.