There appears to be confusing and incomplete information about the PCIe SSDs in mid-2013 MacBook Air 11" and 13" (especially the 128GB models), where a different queue depth may result in different speed test results. http://www.anandtech.com/show/7085/the-2013-macbook-air-review-13inch/8
In simple terms, how how much slower is swap on the 128GB PCIe SSD compared to the main memory on the 4GB LDDR3 in the mid-2013 MacBook Air 11" and 13"? What about 256GB?
I cannot really find any comprehensive comparison on the topic specific to the proprietary SSDs used by Apple in mid-2013 MacBook Air, especially comparison between 128GB and 256GB models. A good answer would include methodology through which it's derived.