Unreal Launcher Downloading 4.2.0 on Mac uses high CPU and brings Finder to knees

Unreal Launcher still needs more work. Downloading 4.2.0 is causing fans in my Mac to double in RPM speed and causing my Finder to stutter about like a drunk trying to navigate a sidewalk. Not sure what all download drama is about, but normally when I download something (say) from internet, there’s absolutely no noticeable performance hit on my system. Launcher also seems to hog memories.

OS X 10.9.3
Mac Mini, i5 CPU, 8GB Ram

Launcher updated itself (v1.3.0), then I re-opened it, then downloaded 4.2.0 (today @ 2pm PST)

Hey ,

Thanks for your report! We are aware that Launcher and install process uses a lot of CPU on Macs, and it is something we’re looking into. Could you tell us your complete system specs? You can find this in About This Mac > More Info.

As a small help, you can quit Launcher once you have Editor open to lower some of Memory drain on your system.


I have half a mind to think you wrote Launcher using Adobe Flex (Flash), it sure feels heavy like that. System info is: Mac Mini (mid 2011), CPU 2.5 GHz Intel Core i5, 8GB 1333 Mhz DDR3, AMD Radeon HD 6630M 256MB.

Hi jcsnet,

Unreal Engine Launcher is actually written with UE4 Core & Slate, with everything being rendered in OpenGL. Your Mac is below minimum specification for UE4 so editor may run slowly as your Mac has a low performance GPU with comparatively little VRAM. A 1GB VRAM AMD or Nvidia GPU is generally required for Editor to run well.

, something else to consider. I use Cinema 4D (like Maya, but cooler) and Unity3D (plus a host of really neato graphics apps). They each perform uber zippy on my system. As AWESOME as UE4 is (thinking about getting a UE4 tramp stamp), I’m having a hard time coming to grips not only with Launcher, but also Editor, which is very jumpy only by trying to orbit simple, low poly geometry. If C4D and Unity can make my 3D experience enjoyable on my mid-range mac (which again is still an awesome machine) then I think you guys can too, better than anyone I believe. I make iOS apps, I’m not going to lay out thousands for a Windows high-perf custom system, nor blow thousands for a new Mac just so I can make my really cool UE4 side-scroller. hardware I have and many still have is super for 3D content creation. I believe you guys can do better.

Yes, I do realize that my system is mid-range yet it’s still an amazing machine. But still and you have to agree, Launcher really shouldn’t need a high end NVIDIA graphics card, nor can I rationalize (from using it) any reason why it needs my GPU. I mean all it does is act like a blog and app launcher. It certainly shouldn’t be giving my Finder a seizure by simply downloading a file. Come’on now. You guys are uber-super-smart, you should know better.

Hi ,

A few things, Slate uses OpenGL to render widgets, so that’s why it uses your GPU. I mention it only as your assessment is quite right, much like main UE4 renderer and things like Flash it updates and re-renders all widgets each frame. Launcher isn’t generally slow because of Slate though.

It could be because your machine only has 8GB of RAM as when installing UE4 Launcher caches download in main memory, which as download progresses doesn’t leave much room for other applications. Quit everything else and then use ‘sudo purge’ in a terminal window to flush disk cache and give your machine some breathing room.

Your machine is much like my own 2009 27" iMac, with its ATi Radeon 4850 512MB, at lower end of GPU performance so it won’t provide ideal UE4 experience. Hence why both are considered beneath minimum specification. UE4’s renderer uses more complex shaders even in simple scenes versus other engines, hence why it requires faster hardware. That is unfortunately price of progress.

To improve matters you should disable realtime viewport rendering ( Down arrow in top-left of main viewport) & reduce Engine Scalability Settings to Low from Quick Settings toolbar. That should help reduce amount of drawing and texture detail to improve performance.

Thanks for reply, well said … but whispers, please make it work better on mid range systems, i5’s, i7’s – 8GB of ram is still pretty darn good these days. Maybe to accommodate (pretty much all) mac’s that aren’t PRO [which no one owns nor can afford] you can throttle down shader math in Editor? I mean, if I’m going to make iOS games or for that matter OS X games, they just gotta run smoothy for masses [on existing hardware]. Editor and (certainly) Launcher should reflect those efforts. I like UE4 – I think I would really enjoying using it and making money with it, but it just has to work smoothy on all standard (modern) Mac’s which majority (of Mac owners) own. From your well said response, I sorta get impression that you guys wrote UE4 (Unreal Engine in general) to work ONLY on high end systems and to that end, although most Macs today I would consider “high end” – you really don’t get BALLS UE4 is expecting unless you build hardware yourself, which means (wink, wait for it…) Windows! So it would seem that although you made UE4 available for Mac, you sorta did so smirking and grinning, nudging your buddies, saying “Haha… look it launches on Mac, let’s ship it!”. If for nothing else, consider this – what is UE4’s carbon footprint? How much energy does UE4 demand from a system? If Launcher alone doubles my fan speed, it also increases my electric bill and amount of pollution going into atmosphere (multiply that by # of seats using Editor and # of seats using Engine in game). If you don’t want to think MAC, then at least think GREEN and by doing so, MAC will benefit.

Agreed with 's statement here. I normally have C4D and Unity open at same time with complex scenes in both and have no issues with performance on my iMac (Latest gen, top GFX, i7, 24GB of RAM) but UE whilst much improved with 4.2 is still very laggy indeed. even with nothing in viewport. editor itself is slow.

Sorry for bump, but I recently posted about Slate and High CPU. On my , Slate in itself uses about 70% of my CPU, while editor only uses ~10%. This really needs to be looked into. Fixing Slate would make both launcher and editor much more efficient. Here is my post.

Using Instruments to profile editor and launcher, I find high CPU usage from Slate’s Tick() and DrawWindows() functions.

current version of Unreal Launcher should not be consuming unnecessary resources. It should be capped to a reasonable frame-rate given that it is an application and not a game, will prefer integrated GPU rather than always activating discrete GPU and so vast majority of processor time it now consumes while downloading is related to uncompressing and verifying downloaded data.

download process uses memory mapping, which improves performance but means download data consumes memory, so for machines with 8GB or less paging of memory may occur if insufficient free system memory is available. This will result in increased CPU usage and will return to normal once download is complete or memory is freed by closing other open applications.

UE4 was very much designed to run on high-end, D3D11 class GPUs, so comparing UE4’s high-end realtime renderer with those of CAD programs or much simpler renderer provided by Unity is misleading. They do not perform same graphical effects, so run much faster on less capable hardware.

Mac version of UE4 is comparable with UE4 running with OpenGL renderer on Windows and minimum requirements really are what is required to obtain a satisfactory experience with these new graphics features. Machines with only 256Mb of VRAM, or which only support OpenGL 3.3 on OS X, are low-end rather than mid-range now as they lack performance required and aren’t officially supported as a result.