I found something odd. Adding this line to the Windows hosts file:
0.0.0.0 dota2.com
noticeably increases my FPS in Dota 2. In some scenarios it gets very close to 320 FPS, which is my monitor’s refresh rate.
My system: Ryzen 7 7700, RX 9070 XT, 32 GB DDR5
Before finding this, I compared low and high graphics settings and saw very little difference in FPS. Blocking www.dota2.com made a much bigger difference.
I also captured several Dota sessions with Wireshark. The client regularly connects to www.dota2.com. It also uses cdn.dota2.com, which serves things like Dota React videos and other UI content.
I get a similar performance improvement from:
map_enable_portrait_worlds 0 in launch args
but that isn’t a good permanent solution for me because it breaks Dark Carnival and some other UI elements that rely on background worlds.
Regular matches still work normally for me with www.dota2.com blocked.
There are some obvious potential downsides, though. Blocking the domain may prevent Dota from loading:
- news and parts of the main menu;
- patch notes;
- videos;
some dashboard/data content.
A future Dota update could also change what this domain is used for.
To test it, add the line to your hosts file, run:
ipconfig /flushdns
Without the hosts entry, my FPS progressively degrades from match to match. The first game starts at around 300–310 FPS, drops to roughly 200–220 after about 15 minutes, and ends at around 185–190 FPS.
The next game already starts at around 200–210 FPS and can drop to about 160 by the end. Another match may start at only ~180 FPS. If I keep playing without restarting the client, it eventually bottoms out at roughly 100–120 FPS.
After adding hosts file entry, the behaviour changes significantly. I played three matches in a row and the progressive degradation was basically gone: average FPS was still around 300 even after the third match.
That makes this look more like some kind of background workload accumulating inside the client rather than a normal constant CPU/GPU bottleneck
I’d be interested to see whether anyone else can reproduce this, especially on CPU-bound systems. If you test it, please post both average FPS and 1% lows if possible.
upd.
How to do it:
On Windows, open Notepad as Administrator, then open C:\Windows\System32\drivers\etc\hosts. If you don’t see the file, change the file type filter to “All Files.” Add 0.0.0.0 dota2.com at the end of the file and save it. Then open Command Prompt as Administrator, run ipconfig /flushdns, fully close Dota 2, and launch it again. To undo the change, simply remove the 0.0.0.0 dota2.com line from the hosts file, run ipconfig /flushdns again, and restart Dota.
upd2.
I’ve opened a proper bug report in the official Dota 2 GitHub tracker: Issue #35438. If you’re experiencing the same progressive FPS degradation, please consider leaving a 👍 reaction and, if possible, a comment with your hardware specs and your results with/without blocking dota2.com. The more independent reproductions and data we can gather, the easier it will be to show Valve that this issue is reproducible across different systems.