Unless your power was already up in pro levels, that's a big improvement. At least 10%, maybe 20%? It's also relevant where the power is being metered. If it's at the pedals or cranks, the new bike and everything else is all "downstream" of the power meter and can't affect the power reading. If it's at the hub, the bike could be implicated somewhat, but I can't see anywhere near that much change. If you had an absolutely filthy drivetrain and cleaned it, I don't think even that would account for all the difference.
Is your position on the bike different? That can account for some improvement, although again, I'd be surprised to see this much change. The simplest explanation would be miscalibration of the power meter.