Haswell-E, lightmass & packaging

Does anyone out there use Haswell-E processors for UE4 and compared them to other intel chips?

I need PC upgrade and would love to know if the extra 2-4 real cores make a noticeable difference packaging and lightmass generation times over an overclocked 479x…

They’re more powerful, sure. It depends on how much you overclock a 4790 if it might be faster than a Haswell-E. But you could also overclock the Haswell-E

Lightmass will use all threads you throw at it (minus 1 or 2, this is configurable). The gains are going to be proportional to the number of cores, so if you previously had only a quad-core PC (8 threads) then get an octo-core (16 threads) then you should see nearly half the lightmass times in most cases, assuming the same clock speeds in both PC’s.

As an example, last year we shipped Betrayer on PC, I was the one responsible for building static lighting for huge landscapes in UDK/UE3. Everyone had quad-core PC’s except me; I had a hexcore (12 threads) Asus Z-79 Pro. Most of those levels took 3-4 hrs to build lighting for me, and one or two special levels in the 6-8 hrs range… but for my colleagues on quad-cores usually meant waiting overnight for lightmass and sometimes not past ~50% in the morning and so they’d end up just cancelling the build.

Also I believe lightmass computes on a per mesh basis, so lots of small meshes with small lightmap sizes will get distributed nicely across the threads, but large dense meshes with high lightmap sizes will use a thread longer. So in many cases most of your threads will sit idle at the end of the build waiting for the last thread or two to finish up on the larger meshes.

In UE4 Lightmass, work is still distributed on a per-mesh basis, however when it comes to building a single large resolution mesh lightmap all the other cores help out too. This is a big difference from UE3 where building one 1024 could take 30 minutes on highest quality when the rest of the cores were sitting idle. In short, UE4 lightmass scales much better to multiple cores.

Thanks guys, I suspected that this was the case, but would to see some real world examples.

I’m hoping to see that an 6 or 8-core Haswell-E is a better investment than a top end Skylake this summer, considering the small IPC jump SL has over BW & HW, and Broadwell-E looks to be cancelled (shame, 10 real cores would be lovely).

There’s a deal on Haswell-E prebuilts on Slickdeals right now, http://slickdeals.net/f/7948357-hp-sitewide-desktop-laptop-rebate-up-to-250-rebate-30-extra-off-hp-phoenix-i7-5930k-more-820-ar-5820k-gtx-980-995-much-more?

5820k - GTX 980 - 16GB DDR4 for $1031

We need a lighting and packaging benchmark alongside the CPU & GPU one :slight_smile: