This problem is where the midi data you record into Cubase is not actually recorded as you play it - the midi data is actually recorded into the sequencer "x" amount of steps behind what you actually played. This is not a latency issue.
The "x" amount increases with time:- the longer you leave Cubase running, the further behind the midi data is placed into the Cubase sequencer.
I won't go into more details because, if you have had this problem then you will recognise these symptons and all I want to know is have you solved this problem using Cubase VST5 (not SX or VST32/5)?
I know this topic has been mentioned many times on the Cubase forums, but a cannot seem to find a definative answer to the problem of Cubase VST5 timing issues on XP.
Thanks for your time