I start to realize this problem with SCII after I solved my low FPS issue with Dead by Daylight game few weeks ago with my gaming rig specs:
Windows 10 Home 64-bit
Intel Core i5 2500 @ 3.30GHz
8.00GB Dual-Channel DDR3 @ 665MHz (9-9-9-24)
ASUSTeK COMPUTER INC. P8B75-M LX (LGA1155)
GeForce GTX 1060 6GB (NVIDIA)
111GB SanDisk SSD PLUS 120GB ATA Device (SATA3 (SSD)) [for OS]
931GB Seagate ST31000528AS ATA Device (SATA2) [for SCII installation]
With all these I got only approx. 50% CPU usage & 50% GPU usage in Task Manager at EXTREME Graphics setting when battling in crowds using Dehaka and the other 159/200 zerg units, I feel tremendous FPS drop to roughly 35-50 FPS in 75Hz monitor.
I used to have same problem with Dead by Daylight game with a bottleneck of 57% CPU & 76% GPU usage which I had posted the bug report for it.
The FPS bottleneck was caused by a faulty VSYNC which auto enabled by default in ULTRA graphics setting.
Because of this, the game engine is not able to make CPU utilize or squeeze out all the power from the GPU to the limit of what it was built for.
In other words, some of CPU’s limbs were cut off by this internal game production mistake.
To leave many gamers with high end gaming rig to run SCII like using a downgrade CPU & GPU from back several years ago.
In the case with Dead by Dalight, is the VSYNC was faulty. But I don’t know what is causing the bottleneck with SCII because I’ve tried turning off the VSYNC and the problem still persist.
Yeah, I’m currently looking to BUILD a PC to optimise streaming SCII… but I’m unclear what I even should be buying.
It’s a bloody pain in the butt… and even Blizzard doesn’t seem to be open about the issue.
it’s a ram/SSD bottleneck - 50% usage doesn’t mean it isn’t at 100% internally: it means it is waiting for something and the average shows up as 50% (you are only seeing averages even if you poll the usage at 1000hz).
I will really suggest you not do so because no matter how high end your gaming rig will be, if it’s game engine faulty, you really shouldn’t break your bank account in the first place.
There’s just one faulty game engine component that bottlenecks how CPU is being used by the game engine.
If you run a game but:
CPU almost 100%,
GPU 50%,
FPS is bad;
it means the game engine is working perfectly but your CPU lacks core to render the game smoothly because there’s still much memory unused in GPU. Then it’s the time to upgrade to better CPU.
If you run a game but:
CPU 60%,
GPU almost 100%,
FPS is bad,
it means the CPU has enough power to render all the frames perfectly, but only your GPU ran out of memory which creates low frame rate. Then it’s the time for an upgrade to better GPU.
If you run a game but:
CPU 60%,
GPU 50%,
FPS is bad;
it means there’s a faulty game component which cuts off the ability for the CPU to render the game at full frame rate.
One day there’s a need for everyone to become self-taught computer engineer.
In other words one can understand a little or more about how CPU, GPU, RAM, HDD, SSD works, so one can live peacefully with technology.
Trying to solve game performance problem by buying better computer hardware without looking at Task Manager performance chart is like gambling. And that’s another great way to break one’s bank account.
Hello Magic,
Starcraft 2 use only 1 CPU Thread on 100% and a 2nd Thread with ~30%.
I assume Blizzard will never repair this issue, because it would cause very many work to fix that.
Please change the view in Windows Task Manager (show logicalic CPU instead of full capacity)
Your CPU i5 2500 is pretty old, and the FPS drops more and more if there are many units on the map. I think on 1v1 you have much better performance. 
If possible upgrade your computer to Ryzen 3600x CPU, or i5-9600, that has nearly double “Single-Core-CPU” speed than i5 2500 
Hello Whte,
If you want to Stream your games, you should buy a CPU with 8 Cores / 16 Threads, that means: Ryzen 3700 or i9-9900, both are same good but Ryzen is much cheaper. Use a good CPU cooler to avoid heat problems on CPU, because Game+Stream cause high CPU workload.
16 GB DDR4 with 3000 MHZ should be clear, Graphic Card is less important, a GTX 1660 Ti would be already sufficient for 60 FPS in Full HD in Ultra Settings.
I suggest a large SSD with 1000 GB for Streaming PCs, … and fast Internet Speed of course, with 100/40 MBit at least.
kind regards,
Bernd