I'm planning to buy a 27inch iMac 5k, but have been hesitating over expectations of a Skylake version. But I am not sure the Skylake version will be substantially faster for my main applications (lightroom and photoshop.) The processor speed is <10% better. And, these applications benefit as much or more from SSD speed/bandwidth as processing speed. The biggest performance benefit from a skylake version of the iMac for my applications would come from increasing the # of PCIe lanes to the SSD from 2 to 4, while using a faster SSD of the Samsung SM 951 or Intel 750 class. It occurred to me to buy the current model of the iMac 5k and attached an external ssd over thunderbolt. I saw this website with such an ssd which tested well showing speeds in the 1.2-1.4GBps range (about 50% higher than the internal SSD in the iMac.) http://barefeats.com/hard208.html Has anyone tried this with their iMac, and if so, what internal drive did you use and how did you make the external TB SSD the boot drive? Thanks.