After hours and hours of fiddling around with GT4, I'm actually getting somewhere, and so am quite pleased.
However, last night I was playing back something I'm writing, which at this point is just a few drum tracks (loops) and a guitar track that I'm just using as a guide track so I don't get lost.
During playback, the tempo sometimes slows down - for no apparent reason - my first thought was that something was running in the background on my laptop, but even after a restart the tempo slowdowns still pop up.
Any ideas what could be causing this?