You need to check your settings.
Advanced View => Tools => Computing Preferences => Processor Usage tab => While processor usage is less than X percent ( change this to whatever you are comfortable with. Putting 0 means that you disable the feature)

Then go to the disk and memory usage tab => Leave application in memory should be checked so that you don't start from the beginning/last checkpoint each time it suspends.

To be sure, the default for 'new' members starting from a clean 'Default' profile is...

Suspend work if CPU usage is above 50 % of cpu

WCG considers that's double BOINC's 25% default is save. It's trial and error, depending on the user applications [My Linux requires 35%, else CEP2 crashes when certain sys-functions run].

This function, unloading the tasks by default [LAIM not out-kicked off such as with benchmarking], I've questioned in past. Such peak loads often are just very momentarily and you can loose hours of progress on an 8 cores, worse for e.g. CEP2 [But for CEP2 WCG anyway recommends for LAIM to be switched on]

LAIM = Leave application in memory [when suspended].

[OT]What would be nice if we had a button in the profiles that allowed to restore absolute [current] defaults... a Clear like we have in the client to remove local preferences. Once you've customized a profile, only way to get them base defaults back is doing it manual from a reference FAQ in Start Here. Does saving a profile back by selecting one of the preset-profile restore these? [Guess not, given that this only works for the preset-profile elements]. Please read this techs... is there a sequence that allows to bring very original default values back in a device profile? :D[/OT]

Not sure what you're saying... if a device is not associated with any device profile, and default is not ticked on any of the device profiles, imagine the hard coded BOINC defaults take over. Big but, if you do not empty the data_dir, an uninstall / install will simply pick up whatever was already in the last fetched general prefs from the server.

Anyway, absent clarity, think this is a thing for techs to provide in the device profiles... a reset to 1.1.1970 state so to speak.

Setting a profile back with radio button to one of the presets seemingly does not touch anything but those 7 or so fields that make up a preset [See FAQ for the set]. You may remember, when altering anything under custom outside of the preset fields, a save and recall just shows the pre-set radio button that the profile had before the customization, and ilicits alerted members thinking their profile changes have not saved. Opague, plus here we have at WCG a mix of preset bolt-ons with standard BOINC location profiles. A standard BOINC profile has explicit separate screens for editing project specific selections and those that are almost all mirrored in the client local pref screens.

Phew, my head hurts and glad it's TGIF.

On this comment I made:

"Anyway, absent clarity, think this is a thing for techs to provide in the device profiles... a reset to 1.1.1970 state so to speak. biggrin"

Of course the timestamp has still got to be the present, else the server would not push the newly restored defaults back to the client whence it connects.

(There's awareness and admitting at Berkeley, even very very recently. The whole prefs thing requires major redesign, but then they've known that for years. You may remember Didactylos made a rebuild with scrollbar and tree structure... simple drop into the BOINC program dir to get the new prefs interface. When I tested that, what 3-4 years ago, it looked very good... it never made it to Berkeley [shunned?], never made it into Synecdoche
either [they had this -remain fully compatible with Berkeley- thing]. Last of their builds.... 2009.