There is a new RC Viewer out: MemShine Viewer version 188.8.131.520582. This viewer is a combination of versions; MemPlugs Viewer version 184.108.40.2060405 and Sunshine Viewer version 220.127.116.110131, I have been writing about for 3 weeks or so. I think this version has new fixes for each of the parent versions.
This combining of RC versions appears to be an attempt to speed up the release of changes made to the viewer. It seems once again viewer release speed is holding things up. Limiting viewer releases to two per month is a basic guideline the Lab adopted to avoid annoying users with too frequent updates. It would seem the result is things are backing up.
I expect a new main viewer version to roll out late this week. If there are problems, that may not happen. But, I think chances are good.
I have been comparing the Firestorm 4.6.5 (64-bit) and SL Viewer 3.7.8. I find both start to have problems in crowded regions. In deserted regions my viewer makes 30 to 60 FPS in most regions. In crowded regions I am doing good to get 20 and 6-12 is common. Checking region servers in poorly performing crowded areas shows problems too. It is hard to know whether it is the viewer or server contributing the most to slow downs. My impression is it is more viewer than server as I see often see good server performance when I have low FPS rates.
Let me know what you are seeing with your viewers.