27'' iMac ''suspended in time'' !?..


hi guys

it's been a month i bought a 2013, 27'' iMac i5 ( 3.2GHz, GeForce GT755m, 8GB RAM + 16GB Transcend RAM i added ) & after MANY yet to be solved USB 3.0 issues w/ both my 1 year old NewerTech Guardian Maximus enclosures ( the 3rd, new one works FINE but i'll spare you - got an Apple Tbolt/FW800 adapter to be able to function.... ) i accidentally managed to erase a 3TB drive

i got Stellar Phoenix Mac Data Recovery to try get back as much data back as i could....

so far so good, problem is my iMac seems to ''hang up in time'' every so often !!

it's not going to sleep, it's not shutting down it's ....as if time stands still to it ? it's very weird & as a consequence Stellar Phoenix is taking FOREVER to get it's thing done - it's been days & days now... - VERY frustrating...

i went into System Prefs, (un)ticked all the boxes to keep it awake, except for the display

i've restarted the computer, checked if i installed the Transcend RAM correctly & tested it ( all good.. ) reset the SMC, the NVRAM, checked my temps & they seem perfectly alright, iStat Menus showing typical results - core 1 through 4 between 54º to 56º C

best way i can describe what happens is that after i'm away for a while, upon returning the screen is dark ( as it should, right ?.. ) i tap the space key, it takes a couple of seconds for it to come back BUT with a catch : the hour on the clock is NOT correct ( late.. ) & there is absolutely no activity in the Stellar's app window's status/activity bars
then the iMac's clock only ''adjusts'' itself to the correct time some 8 or 10 seconds later & so do the blue status bars in the Stellar app window ''come back to life'' for lack of a better description - even only then does Apple Mail receive emails if there were any sent while it was ''comatose'' or inebriated or whatever it is it's doing

while i'm at the computer, the app progresses pretty fast recovering files, the only workaround i've found so far being making a huge list of YouTube videos to play one after the other
the same happened while scanning the drive making it a VERY TEDIOUS & long process, much longer than it normally would...

as it is right now, i'm still 1.2TB away from an almost full recovery ( seems Stellar managed to get back almost 2.5TB out of the 2.7TB of data i deleted - thank goodness for that !.. ) so i'm obviously weery to try something that might interrupt the process & have to restart from scratch but still i'd like to ask if anyone has experienced this or has any ideas what is causing this behaviour ?

in human terms it feels as if you're waking up someone in the morning that stares back at you w/ a hazy look in it's eyes & mumbles something only becoming coherent & LOOKING at you a couple of minutes later, you know what i mean ?

what could possibly been causing this ? any suggestions will be very welcome

many thanks for reading

It sounds like it is indeed being very slow to wake up. What version OS are you running?