is UE4 support octa or hexa cores without rest of some cores?
If i remember correctly, UE4 does not use 6 or 8 cores by default, as it uses specific threads for Rendering, Physix and Logic. However, you are free to spawn new threads for your own asynchronous tasks at any time. However, this statement needs confirmation, as i don’t know this exactly.
The UE4 editor supports Multicores + Multithreading out of the box. When you are compiling shaders, building lighting, ect. It will use as many cores as you can throw at it. More cores will mean these processes will complete faster then on computers with less cores.
I myself use a i7 4930k and I can say it will use every single core you throw its way.
sorry, but could you find something about this?
i am having difficult cause i am not a english speaker ㅜㅜ
under thing is A new, community-hosted Unreal Engine Wiki - Announcements - Epic Developer Community Forums
this site’s recommend
Building a Computer for Development
If you are considering building a powerful machine for UE4 development for around $2500, here is a spec we recommend:
Intel Core i7 4930K processor
Intel X79 chipset motherboard
32GB RAM
1TB SSD
Nvidia GTX 770 video card
they recommended i7 4930k(hexa-core)
then, does it mean ue4 support hexa core?
You not understand how multithreading works
Cores usage is not managed by applications but system kernel which control process scheguleing, process generates threads and system decides to which core to assign it. Single thread can be executed only in single core as we as more threads can be also executed on single but it can be in diffrent cores. So UE4 will use as much cores as system current state allows and how system decides, if other processes use other cores more system will pick more free core, the more process have threads (and it can have more then cores) the more cores it can use… but it dont need to
thank you!
My log says Page size=4096, Cores=4 in a fx8320 8 core cpu
¿Is right?
[2015.05.27-07.34.24:171][
0]LogTaskGraph: Started task graph
with 3 named threads and 6 total
threads.
[2015.05.27-07.34.24:225][
[2015.05.27-07.34.24:259][ 0]LogInit:
CPU Page size=4096, Cores=4
“So UE4 will use as much cores as system current state allows” - only if it’s written to do so, which seems to be what the OP is asking. The system determines how many cores an application can use, but the application architecture determines how many of the available cores it will use.
Didn’t i say " the more process have threads (and it can have more then cores) the more cores it can use."?
OS scheduler, divide work on cores between process, thats why you allways have usage on all of them, single process get assigned to single core, in order for single process use more them one core it need to logicly devide it self, and thats what “Thread” is (if you got good process list software you can see it threads too). If you use “show threads” or profiler you will see that UE4 have around 12-17 threads, things is only 2 of them are heavy duty GameThread and RenderThread, rest are less important (if you got to profiler, threads are named there and you can see what they do). So technicly UE4 uses all cores, but only 2 for game and rendering, which require heavier work. I don’t rember where but in UE4 source i seen code that devides ticks between 4 diffrent threads and number of threads was limited to const vartiable, now i had problem to find it.
Maybe i missed the point if first comment sorry
Ok i find it! TicksGroups are divided between worker threads i be posting explaination as diffrent anwser 
I post more improved anweser
OS scheduler, divide work on cores between process, thats why you always have usage on all of them, single process get assigned to single core, in order for single process use more them one core it need to logicly devide it self, and thats what “Thread” is (if you got good process list software you can see it threads too)
So N\number of used cores depends on number of diffrent thread is process used as OS devides work of threads between cores
Look in source code UE4 seperates ticks (which are state updates) of single tick group between worker threads:
And number of worker threads are limited to const which is currently set to 8 (was set to 4 in the past last time i seen it)
So 8 cores can be used for state updating, rendering is still single threaded. UE4 use some other threads for diffrent things but they minor to effect performence, you can see then in “show threads” command to profiler. In my case UE4 runs around 12-17 threads, but only part of them really effecting performence,
I have dual xeon E2698 V4 (total 80 core)… when I building lighting only half core is on 100% … and whatn came to 98% building procesing only one core working… can you give mi advice what to do… I can find wher to instal swarm agent! I use UR4
I don’t think you need more than 4 cores for UE4 Editor itself, BUT lighting build benefits from multiple cores, so do MS VS С++ compiler when (if) you build engine and your C++ code.
For example engine build on dual xeon e5-2670 with 16 cores/32 threads takes 800 sec. (eats 18Gb of RAM)
Anything special required for building a machine like that to support UE4? I’m thinking of building one if only for light building? Shader compiling should probably be pretty quick too with that many cores right?
Nope, nothing special. A bit more interesting than building a consumer PC 
You can start with this link Building a 32-Thread Xeon Monster PC for Less Than the Price of a Flagship Core i7
well the 8350 is an “8-core” cpu. Its really just 4 core 8 thread. 4 of its “cores” are just starved and resource deprived copies of the real cores.
Do you recommend Xeon over i7, i9 or Threadripper? Im looking to update my PC in a while and im thinking about different CPU’s and GPU’s any recommendations?
Post this as a new question, as first you should not post questions as answer, if you want to ask something extra use comment (which i already converted for you) and this question is already very old and messy.
Thanks you