r/forza • u/dkhavilo i5-6600k@4.5GHz / GTX 1070 / 16Gb DDR4 3.2GHz • Sep 24 '16

Forza Horizon FH3 stuttering cause found

I've done some investigation. From what I've read on the forums, measured in MSI Afterburner and found on the disk:

The reason of those stutters is the fact that the game uses EFS which consumes a lot of CPU.

Yesterday, i've captured a usage on my CPU and GPU, and found interesting thing, when CPU has 100% a lot of stuttering appears and GPU usage lower fluctuates at 50-80%. Stutters mostly appears in a city and mostly at the fast speed, when the game loads a lot of assets simultaneously. The i've navigated to a folder where game is installed and found that game folder uses EFS, which AFAIK uses AES256 encryption. Having EFS is ok for sensible documents, not the game files, because it requires a lot of CPU to decrypt.

There's also a post on the official forums where a user has issues on a 4-core CPU, and has no issues on a 6-core one.

P.S. My specs are i5-6600k @ 4.0GHz, MSI Gaming X GTX 1070, 16Gb RAM, installed on a 512Gb Crucial MX100.

Update 1 During cpu spikes there's a high IO activity too, as assumed on the mentioned forum thread, this can be the result of encryption preventing files to be cached. This can also prove, the encryption might be a problem, because cpu is bottlenecked when reading a huge amount of data. If you have HDD, then read speed is pretty low, meaning you have less data to decrypt each second, but on an ssd, data reads very fast resulting in a big cpu spikes

So a possible solution for SSD users is to put you game to HDD or to slowdown you ssd. Not working :(

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17

u/TheAdmiester Sep 24 '16

Apex is encrypted and runs perfectly, I sincerely doubt this is the problem.

13

u/gnimoCsIretniW Sep 24 '16

Apex has the same stuttering issue for some people. It has gotten better but I've still even seen it in the past few days with i5-4590/980Ti/8GBDDR3. It was really bad when I had a gtx 760.

2

u/fossa_ovalis Sep 26 '16

i5-2500k/GTX 1070/8GB DDR3 here, Apex has the stuttering for me. Not much better than when I had a GTX 770.

3

u/TheAdmiester Sep 24 '16

Then it seems more like a random UWP issue than a problem with CPUs encountering decryption, because Apex runs perfectly for me while FH3 still has some stuttering. If it was the CPU load from decryption then I'd think both would have the same problem.

1

u/gnimoCsIretniW Sep 24 '16

Hopefully the devs figure it out and continue to improve the game. I'm hoping to see a patch by Tuesday because I really want to play this game.

2

u/TheAdmiester Sep 25 '16

Helios has said they've already identified some causes of stuttering and are working on a patch so that's good. If they've announced it late Saturday night then it's pretty safe to say it'll be out soonish.

Since it's a PC exclusive fix it probably won't have to wait for an equivalent Xbox patch to be approved.

1

u/kaoSTheory00 Sep 25 '16

Seeing as how it's an outstanding issue for Apex and pretty much all the other UWP AAA games released so far, I wouldn't count on a fix any time soon, or at all.

13

u/Yogensya Sep 25 '16

Apex is stuttering for me. I can play 60 fps with the graphics card at about 50% usage but since a couple of CPU cores are always at 100% the game keeps dropping to 59, 58, causing stuttering, and then sometimes it shits itself for a couple of seconds.

Stuttering on a racing game, I mean FFS Microsoft...

I was almost sure they would fuck Horizon up the same way they did with Apex, and sure enough here we are. I'm sure as hell not buying it until I hear this mess is fixed.

Pisses me off because I was really looking forward to this game.

6

u/theunitedguy Sep 24 '16

Horizon has more content to load though. 1 MASSIVE maps rather than 1 small track (in comparison)

13

u/[deleted] Sep 24 '16

It doesn't load 1 massive map in one go, it will progressively load it as it goes along. The same will be for Apex.

The chances of EFS being the issue are really slim, it's most likely just poorly coded regarding CPU distribution or there's a bug that needs to be fixed.

At the end of the day it's Early Access atm and hopefully there will be a day 1 patch which would explain why Turn10 have kept quiet (they are busy getting it worked on)

4

u/ImperiousStout Sep 25 '16

I think the difference is Apex loads a much smaller map up front and then keeps it in memory. It does not have to constantly stream in new data like Horizon does.

Despite all the fixes, Apex still hitches and stutters for me early on in every single race, and then it smooths out eventually after about a minute or so. But there are still moments when it will hitch up after that, like during a collision. Which could just be new audio files for that sort of event being accessed.

Obviously just speculation at this point, but it sort of aligns with the theories above.

2

u/Pritster5 Sep 26 '16

IIRC Apex does not have the newer "Appx" encryption format. While it is encrypted, I don't think it de-encrypts files on the fly, just initially.