OK, I tried changing the affinity settings as per SavaPhoto's suggestions and...well what a difference that made.

HIGH and 0,2,4.

It's highly usable!  I mean it's not lightspeed but it's on par with the previous version, like a breath of fresh air.

Now THAT is an interesting solution....I'm not imagining this it's gone from dragging through mud slow to skipping and bopping like an 80's mental patient.

can someone explain how to change these affinity settings in w7 64 bit please?

Jos

Thank you for the info. I did as described. On closing and reopening LR though, the settings are back as they were before.

Also, my quad cores are numbered: 0,1,2,3 No 4.

Jos

Thank you for your help.

I'll make the .bat file and see how it goes.

Jos

When a support person says something is corrupted they usually mean:

a) We changed stuff and the problem went away but I can't be bothered to figure out why so let's call it corruption

b) I know what the problem was but I'm not allowed to talk about it so let's call it corruption

The preferences file is just plain text so real corruption is easy to spot and I would expect LR to spit out an error if it had any trouble parsing it. I suspect that something written to the preferences by a previous LR version was tickling an issue in 4.1 on your system but that is not corruption.

dbeifeld - it still doesnt fix my issue but does make it more useable. Until tonight when I did some math and this is what I posted to another forum -------some simple math tells me that if I loose only 5 sec an image on average - which is likely low since at a minimum I probably loose at least 1 second for every adjustment and photo change, than I will loose about 1.4 hours for every 1000 photos I process. I am currently working on 3 sessions which total about 7000 photos. That is more than a whole days work GONE. I will loose at least one day a month and at least two weeks a year for a one second lag. So one second might not be slow to some but to a busy pro trying to make a living in the flooded field of photography it really is unacceptable. Today I have spent most of the day trying alternatives to lightroom.-------

Just to make it messier for you, I have the same issue, but I do NOT have a Intel i5/i7 on this machine. Win7 64 bit 8Gig RAM SSD w/ images on sep drive AMD Phenom 9650 Quad 2.3 GHz. Clean load, never had lightroom before. My laptop with a mobile i5 performs better with everyone on 1 drive. I suspect the issue is with 4+ cores perhaps? I tried the affinity trick, and didn't help sadly. Just saying. If nothing else this thread as been an interesting read

Savage - did re-installing Lightroom 4.1 work for you then?