It does the same for me, VST usage under Ableton 8.2.2, Nuendo 4.3.0
I'm on PC, Win XP SP3, core2duo T7300 @2,2Ghz, 2Gb RAM
I have a Motu 828MK3 as ASIO driver, one Origin connected to the interface's MIDI OUT, one NORD piano as piano and MIDI controller.
Under Ableton, when I record each part separately, everything seems ok, but when I launch the playback, Spark is delayed for no reason.
I also got heavy ASIO peaks under Nuendo (see the screen shot), in this case it's while playing the "Rock Drums" Kit, but it happens on every new and complex kits, mostly when playing rides, rim shots, fx, crash or cymbals. In Nuendo, Spark is synced (I mean not delayed) but it crashes randomly when changing kits on the fly, probably due to ASIO usage... ? Session is in 44.1Khz, 16bits, latency is pretty low (see screen shot)
and I have no plugin on tracks. When I deactivate Spark via the on/off button in Nuendo, ASIO falls to near 0, so I guess it's coming from Spark.
Another issue : every time I launch Nuendo, Spark is on, the vst cannot sync with the remote saying "connection failed", so I have to reboot the remote, then try to sync again, and then it works...