To begin with, if someone suddenly does not know what Thunderbolt is and why it should not be confused with USB-C, I advise you to read this article of ours. Given her two years of age, certain things have become clearer today, but most of the information there is relevant.
Now let's move on to Thunderbolt 4. For the first time, Intel talked about this interface at the beginning of the year, and already then we learned that the data transfer speed will not change, that is, it will be a maximum of 40 Gb / s. Actually, the way it is, and the news could have ended on this. But, of course, we will not do this.
So, the new interface is not faster than the old one. What are the differences and are there any at all? They are, but not to say that they are very important. For example, certified universal cables 2 meters long will be released for Thunderbolt 4, which was not the case for Thunderbolt 3. In addition, Intel is working on some optical cables from 5 to 50 meters long, but there is no details about them, it is not clear when they are come out, and it's scary to imagine how much they can cost.
The second difference is that the new controller allows you to create accessories with four Thunderbolt 4 ports versus two in the case of Thunderbolt 3. Also, the new interface allows you to connect two 4K monitors or one 8K. Twice – up to 32 Gbit / s – increased the data transfer rate when connected via PCIe.
One of the most interesting innovations is the requirement on the part of Intel to implement protection against DMA attacks through Intel VT-d technology. The problem is that this is Intel technology and its support is implemented in Intel processors and chipsets. This means that in a PC with AMD processors or the same Apple Silicon, this condition will not be fulfilled. A number of thematic resources have already requested comments from Intel and AMD, but have not yet received them. I think there should be some alternative, otherwise the same new Macs with Apple processors will simply not be able to support Thunderbolt 4.
What is the result? As a result, Thunderbolt 4 loses the advantage that previous iterations of the interface had – speed. USB 4 also offers speeds of up to 40 Gb / s, so it’s not very clear why Intel didn’t want or was unable to make Thunderbolt 4 faster. While the fate of this interface seems vague, it is too early to draw final conclusions.