Compiling time is suspiciously too long!

Even if I just change a single number in my code and do ProjectEditor Win64 Development Build, it takes more than 5 minutes to build.

My Unreal Engine and Project are both stored on my hard drive. After reading this, everyone will say that you should move your Unreal Engine and project to SSD, but I tested building my project on my friend’s PC (doing the exact same changes) and it compiles in less than 15 seconds. My friend’s PC’s performance is almost the same as mine, and his PC’s processor is even a little bit weaker than mine.

PC Specs:-
Ryzen 5 5600g (6 Cores 12 Threads)
8*2 GB DDR4 Ram
Code Editor (Visual Studio Code)
UE 5

Logs of my PC build:-


  • Also On my friend’s PC Unreal Engine and project both are located on HDD.

  • The size of the Unreal Engine on my PC is more than 100GB, so it will be foolish to move the Unreal Engine to my SDD because it will slow down the overall performance of my PC.

  • I am sure this is a fault of my computer and maybe I can find the solution to it with the help of other Unreal Engine developers. I am really looking forward to the help.

  • When I build my project, it barely uses any CPU power. It mainly uses RAM and HDD. I don’t know why, but this is the read speed of my HDD -

  • I also noticed something. It starts the actual building process after 300 seconds. The reason I am saying this is that every time I build my project, doing any kind of change, it takes 315-350 seconds. which concludes that no matter how big a change is, it takes not more than 350 seconds nor less than 315 seconds. So the real build time it is taking is not more than 50 seconds. This observation of mine could be wrong, so please let me know if it makes any sense to you.

  • I also tested my HDD with official software by Seagate and it says that the HDD is fully fine.

Unreal Engine really needs to be on an SSD as does your code and ideally visual studio as well. having it on a HDD will dramatically increase compile times.

I am not really clear of the spec of a Ryzen 5 5600 CPU but I know that when I had a 6th gen i5, compile times were slow until I upgraded to a newer PC. However, the number of cores is only part of the performance - clock speed is critical too. My PC is clocked at 3.8Ghz, boosting to 4.65Ghz which, coupled with the 8c/16t made a huge difference. I looked at benchmarks for the CPU and performance shouldn’t be an issue however.

I note you haven’t mentioned a GPU - they can be critical for UE performance (a 3060RTX or 2060RTX is about the minimum for UE5, I would definitely not recommend on-board GPU).

Prices today for SSD are quite low at the moment and even a SATA SSD would help machine performance (m.2 is better but more costly) - I checked and a 1TB SATA can be obtained for around GBP 70/80EUR so USD is probably around 80+S&T. the m.2 version is probably about 30GBP more.

Looking at the screenshots I see the HDD is maxed out. Do you have additional antivirus software installed such as norton (nicknamed aptly as Machine Killer) as they can seriously degrade performance and compile times.

Finally, and this may sound strange but close the epic launcher - not just minimize it but actually quit the launcher. You don’t need it running. This could help but it isn’t going to solve the performance.

Unreal Engine does actually need to be on an SSD and is stated as such in the requirements for the software. You therefore have 3 choices here, install on the SSD (project too) (this will confirm performance issues), live with the slow performance, or invest in a second larger SSD.

HDD these days are not much use for computing/compiling of code, particularly with Unreal Engine. It is fine for backups and storing asset files (even editing blender files and the likes) or working with C# (think Unity, which is slow on an HDD too)

I hope this helps and answers your questions.

  1. I tested compiling on my friend’s PC and it compiled in just 16 seconds.
  2. I also tested compiling by transferring my project folder to an external drive (this is an 8-year old drive) and it just compiled in less than 20 seconds.
  3. I also compiled it by transferring my project folder to the SSD, and it is also compiling under 15 seconds.
  4. I don’t want to do a super fast compilation, I just want to compile my code by spending only a genuine amount of time. (which generally takes around 15 seconds for small changes).

I think all these above-mentioned things conclude that-

  1. There is no need for me to install my UE on the SSD. Installing it on an SSD will definitely improve the performance, but just transferring the project folder to any other drive (it can be an HDD or SSD) reduces the compile time to 15 seconds from 3 minutes.

This is a good CPU as per price, but the problem here is that while compiling it is not using even 1% of the CPU.

I have RTX3050

Actually, the issue is not price, the main issue is that my PC is just 11 months old and the compilation time is just too much.

I have only the official pre-installed Windows antivirus.

Yes, I also know that. And every time I even exit the Epic Launcher, even in the background.

After all the things I said, it seems that my HDD is quite broken when it comes to reading speed. I don’t know why, but I did the full generic test on it (which fully tests if the drive’s read and write speed is working fine or not) and the result was PASSED. Maybe the official software is kind of not that useful.

I raised a complaint about this to the company. Hopefully, they will fix this issue or replace this HDD with a new one.

If you still have any idea what could be the reason for this issue, please let me know.

And thanks a lot for your detailed reply. You almost covered every software-related problem which is causing this issue.

The difference between an hdd,even thethe best one, and an entry level ssd (SATA) is the SSD is about 5x faster, m.2 is more like 20x or more.
An example from my pc is SATA SSD drive gives 560mb/s, hdd is about 50mb/s and m.2 is around 4tb/s. Compile time is around 2 to 5s for changes, and a full build takes maybe 20 seconds. If I place it on an hdd, you’re talking 10 minutes typical, assuming an internal disk which I also used to do but ended up making space because the difference is huge. Forget USB drives, they’d be even less than half a standard HDD, typically 10 to 20mb/s.

The tools and code for the engine remain on whatever installation drive you place it and the minimum requirements from Epic for UE5 are to install UE5 on an SSD. This is not my recommendation, although I can tell you now from experience over the last 4 to 5 years is SSD is not only desirable, it is absolutely essential for both the engine and projects. This to me is a non-arguable point.

The times you are describing are typical of this level of performance for HDD install of the engine. Unless you have a few million lines of C++ code in your project which would make it the size of the engine which makes 3 to 4 hours to compile, where your engine sits is far more critical than your source. You can also install the minimum setup which is a good bit smaller.

As for your the age of your pc, adding more storage has nothing to do with its age. I started with a 500gb drive and added since then an additional 14tb for storing assets, some internal and others external and I’m looking at adding a other 4tb of SSD over time.

Game development hardware needs to be high end.

Thanks a lot for your reply. I also agree with you that UE and project should be on SSD for the best performance possible because it is written in UE documentation, but the problem here is something else maybe my HDD is broke. I will buy another SSD and shift my project and UE into that but atleast I should be aware that what is wrong with my HDD so that I could replace it. Even when I install something in HDD the verification takes almost same time as downloading it. And not a single point of yours is wrong but here I say again I am getting clues that there is something wrong with my HDD.

I just made 2 partitions of my HDD (500GB each) and transferred them to 2 parts of the drive. Now it is compiling fine.

This topic was automatically closed 24 hours after the last reply. New replies are no longer allowed.