From discussion about how much RAM the native Linux version of nwchem WU uses over at https://forum.boinc-af.org/index.php?topic=7838.msg490228#msg490228.

The test was run during a late September local heat wave and so the computer was downclocked severely and suspended for 8-10 hours a day. First run was lost due to a power outage and 81 hours of work lost from lack of save point. 2nd run is on the same WU which actually was given credit even though it was reported days after the deadline. WU was run in an antiX small-footprint Debian Linux VM dedicated to BOINC running on Windows 7 host laptop.

The WU is a t2 class nwchem and RAM used is measured for each of the 2 threads. Maximum observed usage per thread is 580MB

Work Unit: https://quchempedia.univ-angers.fr/athome/result.php?resultid=34852

Task 34852
Name	dsgdb9nsd_nwchem,bath02,010558591,nwchem,1570181983_0
Workunit	22185
Created	4 Oct 2019, 9:39:46 UTC
Sent	6 Oct 2019, 11:15:35 UTC
Report deadline	20 Oct 2019, 11:15:35 UTC
Received	7 Oct 2019, 18:11:49 UTC
Server state	Over
Outcome	Success
Client state	Done
Exit status	0 (0x00000000)
Computer ID	40
Run time	23 hours 30 min 48 sec
CPU time	19 hours 30 min 7 sec
Validate state	Valid
Credit	398.57
Device peak FLOPS	2.03 GFLOPS
Application version	NWChem v0.08 (t1)
x86_64-pc-linux-gnu
Peak working set size	572.46 MB
Peak swap size	1,988.55 MB
Peak disk usage	251.48 MB

Observed usage (HOUR / thread 1 RAM / thread 2 RAM / total RAM used by all processes / virtual RAM claimed by nwchem thread / run 1st or 2nd)

NWChem t2
hour 01: 166, 196mb / tot 0658mb / virt 1.2gb ea (run 2)
hour 02: 166, 174mb / tot 0636mb / virt 1.2gb ea (run 2)
hour 06: 166, 195mb / tot 0657mb / virt 1.2gb ea (run 2)
hour 08: 167, 191mb / tot 0662mb / virt 1.2gb ea (run 2)
hour 14: 166, 188mb / tot 0657mb / virt 1.2gb ea (run 2)

hour 22: 162, 170mb / tot 0641mb / virt 1.2gb ea
hour 22: 167, 191mb / tot 0665mb / virt 1.2gb ea (run 2)

hour 29: 162, 190mb / tot 0661mb / virt 1.2gb ea
hour 29: 570, 576mb / tot 1453mb / virt 1.6/1.5gb (run 2) hour unclear as BOINC declares "time of day suspended", yet it's still running.
hour 31: 350, 357mb / tot 1021mb / virt 1.3/1.3gb (run 2)

hour 34: 162, 184mb / tot 0657mb / virt 1.2gb ea
hour 34: 574, 580mb / tot 1454mb / virt 1.6gb ea (run 2)

hour 41: 450, 534mb / tot 1255mb / virt 1.4/1.5gb (run 2)

hour 47: 162, 171mb / tot 0644mb / virt 1.2gb ea
hour 47: 489, 576mb / tot 1376mb / virt 1.5/1.6gb(run 2)

hour 54: 162, 171mb / tot 0645mb / virt 1.2gb ea
hour 58: 490, 576mb / tot 1378mb / virt 1.5/1.6gb(run 2)

hour 74: 490, 576mb / tot 1378mb / virt 1.5/1.6gb(run 2)

hour 79: 490, 577mb / tot 1380mb / virt 1.5/1.6gb(run 2)

hour 81: 485, 581mb / tot 1380mb / virt 1.5/1.6gb

hour 83: 186, 219mb / tot 0798mb / virt 1.8gb ea(run 2)
hour 85: 197, 232mb / tot 0838mb / virt 1.8gb ea(run 2)
hour 90: 264, 325mb / tot 0998mb / virt 1.9gb ea(run 2)
hour 96: 254, 314mb / tot 0971mb / virt 1.9gb ea(run 2)
hour 100: 330, 339mb / tot 1072mb / virt 1.9/2.0gb (run 2)
hour 104: 260, 319mb / tot 0980mb / virt 1.9gb ea(run 2)
hour 110: 283, 343mb / tot 1022mb / virt 1.9gb ea(run 2)
hour 120: 289, 349mb / tot 1036mb / virt 1.9gb ea(run 2)
hour 126: 283, 336mb / tot 1019mb / virt 1.9gb ea(run 2)
hour 133: 175, 176mb / tot 0747mb / virt 1.8gb ea(run 2)
hour 140: 196, 225mb / tot 0820mb / virt 1.8gb ea(run 2)
hour 148: 202, 232mb / tot 0825mb / virt 1.8/1.9gb (run 2)
hour 155: 215, 237mb / tot 0846mb / virt 1.8/1.9gb (run 2)
hour 160: 192, 209mb / tot 0798mb / virt 1.8/1.9gb (run 2)

So, people should dedicate ~600MB RAM per thread they plan on running.

2 core runs 1.2GB
4 core runs 2.4GB
8 core runs 4.8GB