Please note that I'm not an expert on drive performance but I have my statement for you below:
It's my understanding that the number of lanes is a separate specification from the actual throughput speed supported by any one model. Example: 4X throughput from say a E5570 may be different from the 4X throughput speed on a Precision 7710. When I submit my questions to Dell engineering they're not related to throughput speed and historically, Dell does not give out exact throughput speeds per model.
Thank you for your kind feedback. Yes, I plan to get more information on the new models in the near future. Below is what I have so far for your 5580
2FFR0 - M.2 frame ( clip on the end )
X3DN4 -Thermal plate
4270E - End screw
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