If your CPU runs with 90-100% load, then this is one of the bottlenecks.
But it's also good, because not every system uses it's fully performance.
What you can check is if there is a process other than APG, that use the CPU extensive while rendering.
Eg. a virus scanner can influence the system performance when rendering.
Thank you for that. I keep a pretty close eye on what is running and making sure anything that isnt necessary isnt running the background. One of my big reasons for upgrading the graphics card is to allow for 4 monitors. I cant decided whether or not the applications I am using will benefit from a high end graphics card. One of the programs I care about performing at peak ability is APG.
if you take the nvidia Titan as example: it does have "dozens" of cudas... apg dont care about. the relevant peace is the GDDR Memory, the Titan does have 6 GB.
using more than one GPU Card will Support your multimonitor plans, APG will (currently) not Profit... SLI etc is not supported by apg.
so if you have 100 Image panos.... than 6GB graphic Card will not Profit. apg uses the GPU Memory for previews in detected panos. So if you're working on a 1000 Image pano and you used a D800(e) Nikon / Sony Alpha 7(r) and you zoom a lot to 100% in preview Monitor than you will Profit from more GPU Memory.
Same if you use brackets 200 Image pano but with 5 brackets each... 1000 Images in total...
if you currently does have a 4GB GPU Card it makes no sense to replace this with a newer one with lets assume 35% more cudas but with same GB GPU Memory...