On Thu, Sep 07, 2017 at 07:57:58AM +0900, Mark Fletcher wrote: > That's fascinating because I found the opposite -- my circa-2009 > self-built Intel Core i7 920-based machine surged ahead when I upgraded > from jessie to stretch -- really felt like everything was that little > bit more alive. I'd had no complaints about jessie performance but > suddenly everything was that bit nippier.
Video drivers, most likely. Jessie's X used an "intel" driver for Intel graphics chipsets, whereas stretch's X uses a "modeset" driver. Notoriously in jessie, some of the newer Intel chipsets actually needed (or greatly wanted) a backported stretch xserver-xorg-video-intel package for proper performance. (Your older machine may or may not be one of these.) Some older Intel chipsets perform very well under the new modeset driver without adding any firmware packages. I am guessing yours is one of these. Some newer Intel chipsets perform very well after you install the correct non-free firmware package for them. Without that firmware, they will perform very poorly, to the point where you might actually consider reverting to the intel driver, if your personal philosophy is not to install non-free firmware.
