BLOODL3TTERS :
photonboy :
SUMMARY:
I suspect you'll find the FPS drops correspond to GPU load being reduced. That indicates that the CPU is the bottleneck. You can't use "CPU load" as a guide since software rarely can use all of the cores in CPU's. So we go by the GPU load.
Another indicator is that there are more UNITS on-screen. In DOTA again and similar games it often starts off with less units then ramps up and eventually overloads the CPU.
I will test this tonight and get back to you. If this is true, are you saying I should upgrade my CPU?
I'm saying it's LIKELY that a better CPU will limit the FPS drops in DOTA. You can probably Google some information about that.
However, the COST of that would be high since you would need:
a) new CPU
b) new motherboard
c) new system memory (newer CPU's use DDR4 memory)
d) Windows 10 64-bit license (you can't transfer, though you may find one fairly cheap at Kinguin (dot net) and people I trust claim it works fine. You would download the actual install media from Microsoft's site. Easy to do but I won't detail that here unless needed (basically "ms media creation tool" go to site, download tool with 8GB USB stick installed, run tool and it will then DOWNLOAD the ISO file and auto configure the USB stick so you can boot from the USB stick).
and
e) reinstall Windows, programs, etc (though you can MOVE your "Steamapps" games folder to another drive if it's on the Windows (C-drive) drive then back again or just run from a separate drive (can explain in detail)
*So it's not cheap nor simple to upgrade your system. Again, assuming the issue is the CPU performance then only YOU can decide on the value of upgrading and find which CPU is recommended though probably an Intel i7, possibly one of the upcoming 4-core Intel 8th gen (may be an i5 as naming is changing but basically a 4-core with hyperthreading which is a SLIGHT upgrade over the i7-7700K).
There are cheaper CPU's but if you're going to upgrade your entire system for a game that depends a lot on the CPU you may want to get the best CPU for that game.
Or will a SOFTWARE update to the game help?
This following is several months old now, but I've heard that the game still has FPS drops that it did not have prior to 2017:
http://www.pcgamer.com/dota-2s-performance-issues-drag-on-in-the-months-following-the-700-update/
I don't play the game, but hopefully that last bit helps and you can find OTHERS who can give you better advice because...
*WITH THE UPDATE TO VULKAN ONE HOPES THAT THE GAME WILL BECOME BETTER MULTI-THREADED AND THUS ACTUALLY RUN WELL ON AN FX-6300 CPU ONCE CODE IMPROVES.
But the game appeared to SLOW DOWN not run better so not sure what happened there.
So perhaps WAITING makes more sense, though I repeat I'm not sure what the exact state of the game is today, and what to expect in the near future.