Trying to figure out necessary system upgrade

I got going working with Cubase 8.5 Pro on a new rig within the last year. My rig is an Intel Core i7 @ 4 GHz, and I recently upgraded to 32GB of RAM when I saw projects maxing out my memory. Otherwise, I got a second solid state drive to hold some of my virtual instruments for several SS drives and an external USB spinning drive storing them. That also seems to help performance, definitely helping the instrument patches load a lot faster.

I’ve just been working on a really massive project. This one has been using every major section quite a bit (choir, strings, percussion, brass, winds) and I’m also using the “Spaces” convolution reverb plug-in (everything is EWQL stuff). Suffice it to say, once again, I’m starting to get performance issues with a project this busy like I used to (just obviously not as easily), with instruments dropping in and out and less than perfect mixdowns, with some midi event errors (missing notes, some wrong volumes, and such).

My CPU and memory usage could go as high as 50% while I was working on the project. Where could the performance bottleneck be at this point? People often say I should get a soundcard and I’m getting interested in Steinberg’s recording pack with the UR22 mk2. I’m pretty sure the bottleneck last time was the RAM, which was near the max before and things run better now after the upgrade, but (as mentioned) it’s not going anywhere near that high at the moment. I am using like 6 instances of Spaces though, and some 10 of EWQL PLAY! software, so I know I’m pushing things a bit. I’m also not too good at knowing how to maximize Cubase performance. Again, I’m not sure where the performance bottleneck is this time.