In a lengthy forum post, the Path of Exile developers provided an update on performance issues, graphics driver crashes, and console issues.
Regarding server performance, specifically for Blight, they devs said,
“In Blight, there are a lot of monsters and they have a lot of life. What normally happens when you engage a pack of monsters is that your attacks quickly cull out the weak ones, leaving just a few strong targets. In Blight, however, the weak ones last for much longer. As you know, Path of Exile has a very complicated stat system with tens of thousands of different values that your character can have. Many of these are used in combat calculations and dozens of small buffs, debuffs and ailments are applied to monsters as you attack them. The more monsters there are, and the longer they survive your attacks for, the longer these calculations take. Blight combat is an order of magnitude more strenuous on our servers than regular map content.”
Graphics driver crashes were also addressed,
“While playing certain content (e.g., Betrayal missions), some users experience a graphics driver crash where the screen goes black for a while, and then comes back with a Path of Exile "Map" error. Recent versions of the Nvidia driver including the most recent, 436.30, have this issue. We can't reproduce the problem on Nvidia driver version 419.17. We don't yet know what Path of Exile is doing to cause the crash, but the graphics driver should never crash regardless of what the game does. We have contacted Nvidia to bring it to their attention.
(A few AMD users have reported similar problems but we haven't been able to reproduce this and it doesn't appear to be on the same scale).”
Additionally, console performance was discussed,
"Many of the above problems are much worse on console platforms, due to their hardware limitations. For example, in situations where the game instance server would be overloaded by a Blighted Map, the console's (comparatively slower) CPU is also overloaded doing the client version of the calculations. We will update you as soon as we have progress on this front.”
Notably, the devs apologized for the post not containing more definitive info on how and when these issues will be resolved. They note they wanted to communicate the status of these issues before the weekend. Check out the full Path of Exile post here.