So you can expect some marketing talk and specifications on April 30 but independent performance tests aren't going to happen before late May.
The actual retail launch and product shipments would commence from 27th May at 13:00 GMT. It's the same time when you will also get to read reviews on the new launches. With the launch set for the end of May which essentially lands close to mid-2020, the question arises that how long of a shelve life would Comet Lake-S CPUs as recent rumors have suggested its immediate successor, the 11th Gen Rocket Lake-S family is expected to launch later this year. This would mean that we are looking at less than 6 months before which Comet Lake-S CPUs would be replaced by a lineup that is better than it.