[Solved] FX Chain latency (Lexington - using CA Amp Sim)?

No, not here.    I've used the CA-X amps on almost every project since they were introduced, and I think I may have used Dark Metal on one project.    Same goes for GR5 though which I actually did use twice in my most recent project.    FWIW, I'm also on Win7.    Have you tried temporarily disabling Avast just to test? 
 

Thanks for bubbling this one back up. This particular project was a copy of another simpler project I had used to evaluate Ozone 7 with. Although I had stripped O7 out of it, I had left O5 and channel tools on another track, so a global bypass of effects (E) solved this but raised another issue (since I rarely use FX with lookahead when tracking).
 
The bypass (E) works, and could add in another track, amp sim, no issue. But completely removing FX from the offending FX bin (and even shutting the actual FX bin off afterwards) did not. I ending up saving it with those effects removed, reopened and was "back to normal," but then archived that track just out of spite. I recall scook saying something to the effect of "shutting off an effect in a bin is not enough [for some things], and the FX bin itself must be off." I forget the exact context of his comment, but in my case I had removed the FX completely (O5/Channel Tools) and shut the FX bin off. I admittedly did not check again after saving (immediately closed and reopened the project), but the latency remained after removal. I am not sure if this is normal though.
 
Avast was already off the machine when I did the above (removed it when I did a system restore to get Melodyne Editor 2 back).
 
As for the sims, yes, I have used them before and they are a lot more capable than I was expecting (and actually the quickest method to track ideas I throw back and forth with a friend). Very simple and quite effective.

Thanks for the feedback. Never occurred to me to cycle the audio engine, without closing/reopening the project, that is .