UE4 Dev Rig: Threadripper 1950X or i7-8700K?

Wtf? 30% performance drop is completely unacceptable, either find a less crappy fix or leave it broken.

I upgraded my CPU some time ago (Xeon E3-1231v3 -> Ryzen 7 1700X). I hope this information will help some of you out.

The first thing you need to know is that not every part of game development with Unreal scales with CPU core count. Two that scale really well are compilation and baking lightmaps, which are, incidentally, by far the slowest parts of developing with Unreal. Bear in mind that I build Unreal from source rather than using a pre-built engine.
On my Xeon with 4c/8t a full rebuild of the engine with all the plugins I use took 46 minutes. This was after making some optimizations to my build environment like setting the core count multiplier to 2 and offloading some of the folders to my SSD, as described in the wiki (A new, community-hosted Unreal Engine Wiki - Announcements and Releases - Unreal Engine Forums).
On the 1700X at 3.8GHz with 3200MHz RAM it took 31 minutes. That’s means the CPU alone reduced the build time by roughly one third, which is massive.
After further optimizations I was able to get the compile time down to 25 minutes. The tutorial in the wiki isn’t that good as I found out. During large sections of the build process my HDD was sitting at 100% load. So I determined which folders were being written to so heavily and put them on my SSD, too. The result was that I now get most of the performance of the SSD while building, but still save almost 15 GB. However, if you have a big enough SSD, just put the entire thing on it.
Although I can’t provide any numbers of my own, I can say with confidence that baking with Lightmass will scale even better, because it’s the type of workload that AMD currently excels at. You can look at the rendering times in applications like Blender and Cinebench. Those type of workloads scale beautifully with however many threads you throw at them.

Here are some general thoughts:
You have to decide whether you want to primarily build a workstation for Unreal and also use it for games, or if you want to build a gaming rig and also use it for Unreal. You have to decide, because this will determine which caveats matter and which don’t.
If you want a gaming machine that’s also great at game development with Unreal, get the Intel one because it has better single threaded performance and that matters for most games. Single threaded performance doesn’t matter for the Unreal Editor as much though. What good is pushing 144 FPS or more in the editor? It’s not going to make you a better developer, it’s not going to make the developing experience more pleasant and it’s not going to make you more efficient, so you won’t save any time. And that’s all that a workstation build should be about: making you more efficient and thus saving you time.
Stuff like importing assets and recompiling isolated blueprints is where single threaded performance comes in and there isn’t much time to be saved there in the first place. How much time do you spend importing files vs. working with them? If you change a blueprint, how long is the delay after pressing the play button? Even on big scripts it’s like 1-2 seconds max for me. And Intel’s single threaded advantage is about 10%, so you’re going to save a fraction of a second. Congratulations, you probably wouldn’t notice if someone swapped your CPU for a TR over night.
Sure, that adds up over the course of a project, but you need to be a crazily efficient person before it starts to matter. You’re going to waste orders of magnitude more time browsing this forum when you should be working, casually checking your phone/social media or going out for a smoke.

I should point out that AMD and other processors are also affected. Intel has just been more forthcoming with information / patching.

You’re confusing things here. A lot is going on, but here’s the digest: There are two separate security issues which were named Meltdown and Spectre.
Meltdown:

  • Extremely dangerous in what it does
  • Trivial to exploit
  • Sort of patchable
  • Patch has the downside of producing massive performance penalties for some workloads (games will be unaffected for the most part, although I suspect that packaging games will take a hit, probably not 30% though)
  • Intel only

Spectre:

  • Less dangerous in what it does
  • Extremely difficult to exploit
  • Completely unpatchable (will require new hardware designs)
  • You can only fight the symptoms (patch your application to protect it against Spectre, but unless every program ever written gets updated … well, that’s not going to help all that much)
  • Just about any CPU you’ll find out there affected

The worst case scenario would be if exploit kits for Spectre would be made that allow to exploit it easily. That would be awful. However, for the time being this means that saying that “other processors are also affected” is the sort of disingenuous damage control you’d expect from Intel’s marketing division. No, the worse problem (as of today), is Intel only. The performance penalty is Intel only. And the fact that the other issue isn’t Intel only also doesn’t make it any better for them, because they aren’t exempt from it either.

Also, I’d like to repeat that this won’t make your games run 30% slower and won’t hurt your performance in compilation, rendering or any other form of number crunching either. Where this hurts the most are applications like databases. I think that the worst penalty somebody using the Unreal Editor will notice is in packaging times, but I can’t say how much slower it’ll be and if you’re even going to notice.

lol

[TABLE=“class: table-condensed table-striped”]

		**Google Project Zero (GPZ) Research Title**
		**Details**

Variant One
Bounds Check Bypass
Resolved by software / OS updates to be made available by system vendors and manufacturers. Negligible performance impact expected.

Variant Two
Branch Target Injection
Differences in AMD architecture mean there is a near zero risk of exploitation of this variant. Vulnerability to Variant 2 has not been demonstrated on AMD processors to date.

Variant Three
Rogue Data Cache Load
Zero AMD vulnerability due to AMD architecture differences.

Source

Spectre, Spectre, Meltdown, respectively.

i’ve got a similar rig but with less RAM

Why copy my post?

It’s a spambot. All new users need to have their first post approved by a forum mod. They quote text from earlier in the thread, to make them seem on topic, and come back once the post has been approved and add the spam links. It’s very hard to catch, unless we mods read the whole thread first!.