I am also having this issue. I just installed Lightroom 5 on my Mac Mini (2014) that's running Yosemite. The Mac mini has 16GB RAM, 3GHz processor and a 256 GB SSD. I have a 27" monitor Asus PA27Q hooked up to it. Photos are on an external hard drive connected via a Thunderbolt 2 / FireWire800 adapter.
Can't see that the hardware couldn't handle real-time rendering, so something else must be going on.
Hi. I have the identical problem with the same data (Lr 5, Macbook Pro, Yosemite (the issue was under Mavericks as well), 8 GB of RAM). A month-long conversation with the Adobe's support team and carrying out all their instructions have changed nothing. I store the catalog and photos on the computer's hard drive, so it's not about rendering in my case. I tried optimizing (Optimize performance), increasing the cashe size, reinstalling and so on but all are useless (which is expected for me as my Macbook, OS and Lr are up-to-date and it seems to be not a preferences' but some 'root' problem). They said my computer supposedly has not enough memory (while the system requirements are "2 GB (8 GB recommended)" and has drivers' defects. Which is questionable as the other programs (including graphics editors) work well. In my modest opinion, it can be some bug between Lr and, probably, the Retina high-res display or my kind of graphics card.
I wonder if the issue is systematic.
Thank you. It sounds like you an I have the same setup with the same problem. Hopefully, Adobe reads the comments and does something about this bug.
SeaMonkey1, could I ask you to share some more details of your model please (like year, display, resolution, video card - or just give a link to your Macbook's model). I keep on talking to Adobe and need some more evidence that it's not Apple's (and my) problem, as they said, and to find out if this is a regularity.
If someone else has this issue, please report your setup details here.
Here's my system information:
OS X Yosemite, 13" Retina Display, Late 2013 MacBook Pro, 2.4 GHz Core i5 Processor, 8 GB - 1600 Mhz DDR3 RAM, Graphics Card - Intel Iris 1536 MB, and I've updated with the most current version of LR.
Hope that helps.