I recently upgraded from 7.9 to 7.10, and I'm noticing that when I connect to a persistent VDI, there is a significant display lag for a few minutes. For example, when opening applications or dragging a window looks like a slideshow. When I move the mouse around my desktop, there is a delay before the icons get highlighted. It's not a massive delay, I'd say it's closer to half a second or a couple hundred milliseconds, but it's absolutely noticeable. Even Youtube video looks like a slideshow (but the audio sounds normal). Then after maybe 5 minutes or so, it completely clears up, and there is no longer any perceptible delay for the duration of the session.
I'm using Blast and I have the 7.10 agent, 5.2 client, and this VDI also has a GRID card.