In the Metadata panel on the right of Library, make sure you've selected the Default tagset:
Many versions ago, there was a bug where Library operations would slow down quite a bit if you had anything other than Default selected. It was fixed, but perhaps there's another variant of the bug affecting you.
Also, make sure face detection is paused:
but then it will start to slow, every 5th or so image it will need to load
Select all photos and do Library > Previews > Build Standard-Sized Previews. Wait until it finishes.
When you see "Loading," that means Lightroom is generating a preview.
It's often the case for me, after importing a large number of images from my camera card, I start flipping through my images rating and picking. Lightroom is working in the background, building previews, but I scan through the images faster than Lightroom's preview-building operation and will get past the point where Lightroom is working, and start seeing "Loading."
When Lightroom is building the previews, you see a status bar in the upper left - if LR is still building previews, wait for it to complete and you won't see the "Loading" and experience the lag.
hi John, thanks for your reply, i was already on default and face detection was paused.
Hi Mike, have built the previews and its still happening
Some other things to try:
1. Do File > Optimize Catalog.
2. Exit LR and delete the "catalog Previews.lrdata" file in the catalog folder (where all the previews are stored). (Make sure you don't delete catalog.lrcat!) Then in LR, do Library > Previews > Build Standard-Sized Previews. Wait until it finishes (a long time for large catalogs). Very rarely, the previews database has been reported to get corrupted.
3. Export a copy of your catalog by doing File > Export As Catalog, and don't select any of the options at the bottom of the Export As Catalog window. When you open the new catalog, do Library > Previews > Build Standard-Sized Previews and wait a long time until the previews are rebuilt (yet again). This method sometimes eliminates inconsistencies that have accumulated in the original catalog.
when i go through 1 by 1 each image for flagging/rating, i can rapidly go through the first 50 images (spending approx 1 second on each image) with instant rendering, but then it will start to slow, every 5th or so image it will need to load, then it will start to do it on every image.
Also, when this happens, are you in Loupe view or grid view in the Library? Does the problem happen in both views?
My Catalog preview is 107 GB
and my catalog is 150 000 images
in 2016, is catalog size really a factor thats going to slow it down ...
im always using loupe, but just checked the problem on the grid view and viewing at the largest icon, it still loaded, but a bit quicker then in loupe
in 2016, is catalog size really a factor thats going to slow it down
Many people have reported that LR works well with catalogs of more than 500K images. In general, the number of images in a catalog does not affect LR performance: http://www.lightroomqueen.com/lightroom-performance-debunking-myths/