Like SGX, TSX is a constant problem with Intel's CPUs. SGX shines with various security gaps, TSX is hardly inferior to this. The technology that has been part of CPUs since Haswell has also always been in attack opportunities in the last two years, now Intel is switching it off.
Intel is now dedicating an entire whitepaper (PDF) to the story again, because the effects not only affect one or two CPU generations, but a whole range: Skylake, Kaby Lake, Coffee Lake and its Refresh and Whiskey Lake, in all their versions From core processors of the sixth, seventh, eighth and even ninth generation to the Xeon offshoots from small Xeon D to Xeon-SP to the smallest mobile Pentium CPUs – the model range is ultimately extremely large. For these CPUs it is now simply: “a newer microcode update will be released in 2021.1 IPU that will disable Intel TSX by default”.
The reasons for the current discontinuation of support are likely to be that most consumer products have already been discontinued, the Core i-9000, for example, should be completely phased out by the end of the year, all predecessors are already. However, this is likely to be more serious with Xeon D, among others, these Skylake solutions are still available without a successor, here Ice Lake-D is supposed to take over at some point. > 
TSX has been causing problems since the start
The PDF clearly shows when the problems with the Transactional Synchronization Extensions (TSX) technology introduced in 2013 began: The PDF was published in October 2018, when a large gap was known. But that was not the first time a problem with TSX, it goes back to the start, when Intel was forced to deactivate TSX on Haswell. Broadwell became famous at the time for not offering TSX at the start due to an errata. In retrospect, there has been some problem with the technology in every CPU generation that TSX supports.
And TSX is not the only constant problem child, it is always the same recurring issue is called SGX. This caused massive security gaps in the past. In addition to Hyper-Threading as a gateway, this was identified as one of the greatest weaknesses of current Intel CPUs.
Again, this will mean a loss of performance, because this technology was introduced to provide a gain in performance. As Phoronix reports, who noticed the changes first, Intel once spoke of a 40 percent performance gain in certain applications. With the shutdown, Intel says diplomatically, “Workloads that were benefited from Intel TSX might experience a change in performance.”