Unreal Engine 4.7.5 Lag on adding things to scene

Hello there,
Since some time my Unreal Engine Editor laggs everytime I paste something in the world . It hangs up up to 1-2 minutes. Also Unreal Engine eats then over 6GB of ram what is alot!!! .

I have

Amd Fx 8x4,7 Ghz
Amd Radeon R9 290
8 GB’s of Ram 1666 Mhz
7,5 TB of Hard Drives. No SSD.
Im using Windows 7.
Im using Unreal Engine 4.7.5.

( The problem was still in 4.7.4 - 4.7.5 )
Hope someone can help me.


Hi CLBander,

When you say “paste something in the world”, are you talking about duplicating an actor that’s already in the level or draggin an asset in from the content browser?

Can you tell if it is only certain types of assets (like decals, skeletal mesh, etc)?

Can you send in your dxdiag info (it gives us more info, like driver versions, etc)?


When I duplicate actors & light and draggin. Its with everything I drag in or dupe.

I will try it with Windows 10 right now need to transfer the source files but if im done with testing I will post the result.

cheers- Bander

Hey Bander,

Just a heads up that we don’t officially support Win10 yet and can’t guarantee any better performance (or anything) on there.


Yeah Yeah I know Win 10 and UE4 works better * more fps *. There is no problem with directx and my grafikcard.
Its a problem with the level and the engine.

Update - When I drag something in the RAM will grow up from 3 GB to over 6 GB. When its done it goes down to 3 GB. And the map is without foliage 1,4 GBs big. ? not normal it was before those lags with foliage 800mbs,.

Hey Bander,

How large are the assets that you’re trying to drag into the level? Is the jump from 3GB to 6GB only happening in Win10? 6GB of memory usage and more is expected on larger projects. It really depends on asset size and complexity.


Hi CLBander,

I’m marking this as answered due to inactivity. Simply reply to this answer to re-open the issue.


Hello ,
same problem. Engine freeze, when i try to place objects. Im using the Stones from the Kite Demo, but it never happens before.

Hey vortexman100,

I was able to repro this with the Kite Demo assets. Thanks for opening this back up. I’ve entered it as UE-16308


Hi vortexman100,

The reason you are seeing such a long stall is that the very first time you use an asset it will compress it’s textures into an appropriate format. In the case of the assets from the Kite demo, these are authored at a very high resolution, most of the normal maps are 8Kx8K which equates to a 64 mega-pixel image. Compressing such a large image takes a significant amount of time even on a high end CPU. On subsequent runs of the editor however the DDC will already be primed with the compressed texture, so you shouldn’t see the stall again.

We have investigated using the CUDA compressor included with nVidia’s texture tool libraries to speed up the compression, however we cannot then guarantee that a texture converted on the CPU will be binary equivalent to the same texture compressed using CUDA, in fact 2 different GPUs may also produce different results. This would result in problems with patching.

I’ll enter a new Jira to pop up a progress indicator to inform the end-user that the stall is due to textures being compressed and stored in the DDC.

-Mike T

The new bug Michael mentioned is UETOOL-394.