This sounds like you're running out of RAM. Running 1000 images with only 8GB of RAM for 20MP imagery on High would seem to cause this error. You can watch your memory usage in Windows to see if you're hitting the top end, too.
I would go back to the big machine and figure out why your alignment is coming out so bad. Do you have ground control? Are you aligning to that or only using the camera locations? I'm assuming this is UAV data, so are you using standard GPS locations, PPK, RTK? If it's a DJI using the internal GPS, then you could have a lot of variation between the camera altitudes from flight to flight and day to day. If you're using GCPs, do you have the cameras unchecked when you're optimizing? There are a lot of factors that can cause what you're getting for results.