Do you know if Steinberg is trying to implement a "bridge" in ASIO-Guard for audio processing on CUDA enabled graphic cards?
This could explain why graphics performance seems so linked to plugin performance in version 7.
no, I'm not aware of CUDA implementations being worked on.
The graphic performance appears to be linked to the latest drivers' implementation, with some of the improvements made for gaming and 3D graphics causing real-time spikes with particular plug-ins.
These plug-ins all share common characteristics - they over-ride the default behaviour of the pointer when hovering on the controls, so it might be related to a particular GUI framework.
I'm no developer, so I forwarded the outcome of my tests to the proper people in-house.
They were actually already on it and the GUI handling is being revised - it is quite unlikely that the drivers will be written the "old way" in the future, so it must adapt to the way drivers are working now and will probably work in the near future.
By the way, during my tests the behaviour of Cubase 7/7.5 and Cubase 6/6.5 was the same concerning this.
But Cubase 6/6.5 only shows the average VST Performance, so the spikes and fluctuations might look like a normal fluctuation due to the load, especially with a lot of plug-in instances or working at low latencies.
When looking at the Cubase 7/7.5 real-time meter, it might trick into thinking that the performance is much different, but the only way to directly compare the two versions is by comparing the average meter only.
Hope this helps.