Chosen Solution
Hi All, I am new to this forum but I cant seem to come right with my issue. I have done a fair bit of research but cant seem to come right. My Issue: I have two 27” iMacs, A Late 2013 and a Late 2012 model, both have the same issue. I installed an SSD into the iMac and did a clean OS High Sierra install but the machine “runs slow” if I can put it like that. Anything from opening applications to watching a video takes a while and just seems sluggish. The late 2013 iMac had surge damage but I replaced the power supply and installed an SSD. The Late 2012 model I replaced the HDD for an SSD. After both machines were opened and had the HDD replaced I ran into this issue. I have also tried booting up on an external SSD but have the exact same issue which rules out the SATA cables. I have also remove the SSD from the iMac and used it to boot up on a different machine and it works fine. I am currently just trying to sort out the late 2013 model at this point. I am busy installing Mojave to see if it will make any difference at all but I doubt it as the SSD works perfectly booting externally on a different machine. Any help would be appreciated here. Its just strange that I have had 2 iMacs at different times with the same issue but I have done SSD upgrades to numerous machines over the years and have had no problems at all.
OK, then I think we have to go into the systems preferences and make sure the new drive is selected as the startup drive within Startup Disk. You may want to use this app instead TG Pro as it will show you more details on whats happening with the thermal sensors and fans. If you get the full version the other SMC sensors are also monitored. I personally like this program better than the others.
