The new cpu did not resolve the issue; so I will be sending the R15 back for an exchange or refund.  Thank you and all those who comment and all comments were very helpful and appreciated!
Just received this Alienware aurora desktop system (R15) and noticed high clock speeds 4.3-5.8 GHz at start up across P and E cores. During this initial period (5 min) opening applications are associated with transient increased clocks. Normal. After a few minutes (about 5)  the clock speeds for all P and E cores go to 0.786 GHz. Subsequent opening of apps. or browser windows is NOT associated with any clock speed changes in any core. No transients. The temperatures appear normal. The system passes all of its tests, done with Alienware support and a new cpu install is scheduled. But any suggestions would be appreciated. This type of issue has been noted in laptops, possibly related to battery issues but not notably on desktops. Any suggestions would be welcome. Thanks.
Aurora R15, throttles down to 0.786 GHz