Earlier quoted context omitted.
"Something as simple as finding next text search match takes about a second." I'm not sure how our configurations differ but on a fairly modern machine (say, surface pro 4 i5) I've not had visual studio 2015 slow down, and editing and searching is az zippy as with Vim for me. I've had the experience that some third party tools have bogged down the experience, though.
I mostly run it on a Xeon workstation with 32 GB RAM, SSD, Nvidia K5000, etc. I think you can call it a modern machine. Other software runs fast. I don't have any third party software installed on top of VS2015. Only unusual aspect is that I also have several other Visual Studio versions installed, like VS2008, VS2010, VS2012 and VS2013. I also have many Windows SDK and DDK (driver devkit) versions. But that shouldn'…
It does exhibit strange behaviour (including becoming suddenly very tardy) that only goes away by deleting the local cache files (intellisense db and whatnot) so I'm not claiming it's technically perfect.