Windows 10 seems to cause a lag-like loss of combat updates during high-activity moments

[Gameplay] Windows 10 seems to cause a lag-like loss of combat updates during high-activity moments

TLDR: After exhaustive testing, it looks like something specific to Windows 10 is causing lag-like loss of combat updates during moments of intense game activity. It's happening on multiple machines on the same network, but only in specific circumstances, and not always at the same time on both machines, and only when those machines have Windows 10 running.

Overview Forgive me for the length of this post, but this problem is very annoying, extremely hard to quantify, and there's simply no other explanation I can find for the issue, so I want to be as thorough and specific in detailing the problem as I can, in hopes that Riot can find and eliminate it.

After upgrading to Windows 10, I began to notice small lag-like glitches during gameplay. I've been playing League for years, and like everyone else, I've had those annoying moments where you suddenly realize that you're not actually playing anymore; you're running around, and everything just stops. This problem is not that. A few weeks later, I upgraded the wife's machine to Windows 10 as well, since she hated the 8.1 tiles and kept ending up in the Modern UI at random because 8.1 sucks. As soon as she started to play, it became a problem for her as well. The exact same circumstances were repeated for her.

Now that we had two machines with the same problem, I started testing things. Since none of the tests had _ any _ visible impact, if you just want to skip down to the part where I identify the exact nature of the problem, go ahead. If you want to see what I tested first, continue on. Maybe you can spot something I didn't.

The Troubleshooting My first thought went to Internet problems, but that was quickly eliminated because it was happening to me almost every single game, and wasn't happening to my wife's PC at all when she still had Windows 8.1. When we were in the same game together, she was completely functional and I was lagged at random. My idle FPS is 400-450, and mid-fight it typically hops between 150-300 depending on the intensity of the action. My ping is typically 40-50ms, and during the spikes, it doesn't change or spike erratically in any way. During the lag, I can tab out and browse the Internet, and if I have a streaming movie running, it doesn't glitch at all.

Here's what I tested. After each test we played repeatedly, and the issues remained. No test lowered or raised the frequency of the problem, or eliminated it entirely.

• Graphics options: to shorten the list, I played with every possible graphical option in the Settings panel. Raising resolutions, lowering, quality settings, framerates, etc. No changes.
• I changed from the Killer NIC drivers for my on-board card to the Atheros drivers for both my machine and hers, because I'd seen problems on the web for users working with the OEM drivers. I'd never had these problems before, but I had a new OS now, so I gave it a shot.
• I added a new network card from a different manufacturer to my machine, one specifically listed as Windows 10 compatible. For this test, I kept hers the same.
• To eliminate the Killer Nic potential from the network entirely, I added a network card to her machine as well. Also Windows 10 compatible, but different card.
• I moved myself from the local gigabit switch in our den, directly over to the wireless router in the closet. Still a gigabit connection, but less hops.
• I moved her over to the router as well. This was to eliminate potential network issues with the gigabit switch.
• I moved myself to the raw Internet connection, eliminating the router completely. Still a gigabit connection to the modem, but my outside connection is 60mb down, 6mb up.

After this test, I moved us both back to the wireless router and left the gigabit switch out of the loop. Additionally, we were both still using the new network cards. At this point, I'd absolved the network of commonality problems, and started looking at other issues. We both have the same brand of motherboard (Asus), but I have the z87 and she has the z99. I have a GTX 970 and she has a 770.

• I changed video driver versions on my desktop, going to the newest Win10 friendly build.
• I changed her machine to the exact same driver version she'd had before Windows 10, which rolled her back about six months.
• I rolled my motherboard and system drivers back to the same stable build I had from Windows 8.
• I updated to the newest Windows 10 board/system drivers, which were several months newer than the ones I found on Day 1 of my upgrade.
• I repeated the rollback and update process for her machine. Same results.

At the end of all of this set of tests, I left both machines on the newest stable drivers for all hardware. As I said before, nothing I tested produced any improvements.

Quantifying The Problem All throughout the testing, we'd kept playing, and the problem kept happening. It didn't happen every game, but it was quite a large percentage. I'd be running around with everything normal, and then suddenly, nobody was where they were before, and I realized that I'd lagged out.

At the end of a normal lag spike, I suddenly just appear somewhere, and I see all of the things that are happening at that moment, exactly like skipping forward in a movie. However, during these spikes, it was as if the game's output had been paused, and when it resumed, it rendered the missing time at a hundred times the speed. After it caught up, people were generally in the same place they appeared to be, but all of the missing time occurred at once. Sometimes either I or the others would seem to randomly skip around, but I realized that it was because champion abilities were affecting us, moving us around.

It took a bit of random chance to finally pin it down more specifically. In ARAM, I ended up with Ziggs three games in a row, and in every single game, if I threw all three main abilities at once in a team fight, I lagged out for a fraction of a second. If I was in the middle of the big fight when I did it, that split second became several seconds. Once I realized what I was seeing, I could experiment with it when it happened to us, and I discovered that the champions would still move around, but no actions of any kind would register on the screen. It was as if the game had allowed all of the movement inputs, but buffered the output of all actions for the duration of the lag. It wasn't like a normal lag spike; every movement still registered, and occasionally I would see people's health bars change or even disappear, but nobody would die.

When the wife and I played separate games at the same time, it happened to both of us at different times. When we played together, it mostly happened at the same times. It took awhile before I realized that when we were together, the only times it didn't happen to both of us is when one of us was separated from the action. After knowing what to look for, it was easy to replicate: the more a given game had large amounts of rapidly-chained inputs from a lot of champions, the more it occurred. Additionally, it seemed to be related to champions who could fire off all of their abilities rapidly; Ziggs, Alistar, Karma, Vel, etc. People who couldn't trigger their outputs in quick succession, like Xin or Cait, Tahm Kench, they didn't seem to trigger it as often for me. It doesn't seem to matter what those abilities do (very visible ones, sound-only triggers, etc), just that a large quantity of them are used at once. Cait, for example, simply can't use all three abilities the same way Zigg, Karma, or LB can.

Because we play side by side, I was able to try something during one of the spikes. She had her screen focused on the shop since she was dead, and in the middle of a fight, I suddenly lagged out and she didn't. She re-focused her screen on me, and I started to trigger abilities. As Singed, I was able to enable and disable the poison trail, and I was able to throw someone, all the while running around in the battle with full control of my champion. On my screen, nobody was present except me, but I was able to use her screen to play the game without issue.

Just for the hell of it, because nothing else makes any sense at all, I imaged a second hard drive with Windows 7 and brought it up to the most current the OS would support in terms of patches, drivers, and software. No matter how many games I play in Windows 7, this lag never occurs. Period. I can literally flip operating systems to Win7, and play ten games in a row without issue. I go back to Win10, I have the problem within 3 games at most.

Supporting Evidence

Hardware Information is available here.

Just a quick note: Fraps is forcing a constant capture speed of 38/39FPS, despite me setting the Movie setting to 60. Normal framerates are in the hundreds as mentioned above. I've linked several recent gameplay videos as reference.

Bot Game - 6 seconds in. ~2 second lag; the minions beside the satchel charge move for no reason, but it's really because the satchel charge exploded during the lag. After the lag, when the satchel charge explodes, they don't react to the explosion at all. Also, combat animations happen on multiple champions in the back who aren't even in combat, and all of the animations happen to all champions at once.

Game Sample 1 - The lag happens approximately 8 seconds into the clip. You can clearly see me recall to the Poro King and then I suddenly stop moving. However, if you watch my cursor, I pick an exact spot several seconds away to run to. When the spike finishes (and the bazillion abilities go off at once), I am exactly where I clicked. In the lower right, you can also see Naut running around and then just stop cold. After the lag, he's dead in that spot.

Game Sample 2 - Starts about 4-5 seconds in. Watch Vel'Koz; during the lag he moves, but afterward, his abilities are used. You don't just see the aftermath, you see them appear and disappear at high speed.

Game Sample 3 - This is the example I'd been hoping to capture the entire time; I was in full control of Alistar during the entire spike, and was able to use To The King, and move around and attack things despite total loss of action updates. At the start, I've got my screen focused on the action while I move myself toward the battle after respawning, and the lag that kicks in is enormous. It lasts a good 15 seconds. Every few seconds I catch up a bit, but it's not till almost 20 seconds in that it goes live. My wife did not lag during this entire span. I could see myself acting on her screen, just like above with Singed. I was able to activate To The King despite my lag; you'll see me just suddenly appear at the Poro King during a burst of updates.

Conclusion I'm not sure what else I can provide to start the investigation except to re-state the single most important fact about the problem: it literally never occurs in Windows 7. Ever. Maybe there's something specific about Windows 10 causing the problem, and maybe it has nothing to do with League at all. Maybe it's DX12?

Riot, if there's any specific troubleshooting you want me to do, any kind of debugging tools you want me to run alongside my gameplay, let me know. Nobody is more motivated to solve this than me. It's killing two sets of gameplay at once at my house. :/