That is not correct, as they did not have a Qualcomm X running iOS12 and they clearly stated that in the article. They only compared the Qualcomm X running iOS 11, which cannot be a fair comparison at all.I installed the 2nd beta. My bars are the same, signal strength in the service menu is the same. However when running a speedtest my speeds are about double. I'll check throughout the day and see if it remains constant.
The Intel chip is better than the qualcomm in the X per pc mags test. The issue appears to be antenna design and software.