Lightroom 5

Lightroom help.

I am currently running windows 7 32 bit on a laptop with 4 gig of ram, the bare minimum for Lightroom 5. My RAW photos come out at 21mg. Often I have to batch process these photos for the sake of speed, sometimes I have up to 150 shots.
These photos are processed in the Development mode. However trying to export these into JPG is very slow and my system runs out of memory, it can take up to 4 attempts to export 15 photos.
The best solution I have found is to tag these 15 or 20 RAW developed photos move across to Library mode then close down Lightroom. I also run a program called Cleanmem which I activate and clear the memory. I then reopen Lightroom which opens at the place I was last at Library mode with tagged photos and I export to JPG. All 20 of the photos will export in about 14 minutes, fine by me as I can do something else.
Can someone explain why it is so easy to do this in Library and so slow in Develop?

Probably because the Dev module is the biggest source of the multitude of memory leaks that Lr seems to have, and it's not just in V5. I used V4 from the first public beta until the middle of 2016, since then I have used CC, all of them seem to have serious memory leaks. Closing Lr and either rebooting, or dealing with the memory leaks in some other way will be what is making your exports run better. They would probably complete just as fast if you were in the Dev module, as long as you don't actually make any adjustments. Of course it is usually easier to instigate exports from the library module, since it makes selecting various images easier.

Alan

I should also add that the problems are centred around a Canon 550d 18 megapixels no21mg RAW files. Canon 40d RAW files only 13 mg, Panasonic Lumix Fz20 RAW same size 13mg no problems with these 2 cameras. Pentax 20d not used much but no problems either. I am considering upgrade to Canon 77d but it may also mean new computer, this camera 24megapixels? Some on web suggest convert to DNG but makes no difference.

galelegg wrote in post #18818157
Some on web suggest convert to DNG but makes no difference.

No reason why it should. 24 million times 14 bits of raw data remain 24 million times 14 bits of raw data, whether they are in a DNG wrapper or in a proprietary file format. The only difference is that the DNG may include in the metadata Quick Load Data that speeds up the initial loading of the image by reducing the need to use the CR Cache, but after that everything is the same - writing the edits to the catalog and then exporting by processing to an RGB image in the color space of your choice, possibly resized, output sharpened, reduced to 8 bpc and compressed to the specified Jpg file. None of which is influenced by the source of the original data.