Why does my game keeps desync'ing after the latest patch?

[kwok]

Despite switching to steam support, COH still uses P2P match making which means the game essentially hosted on EVERY computer in game.

So even if your personal computer/network connection is strong enough it doesn't mean everyone else is. Large AI games will usually lead to desyncs because of the pure amount of calculations every single computer that's in the game need to keep track of and stay in sync with one another. AI are usually capable of heavy spamming which means there are hundreds of units to keep track of, their exact state, location, etc. Just a rough extreme example: Imagine a 4v4 which means 8 players times popcap at 250 units with each unit able to shoot like 100 bullets per minute. That's 200,000 bullets to calculate per minute. Each bullet/damage calculation requires at least 4 steps (accuracy calc, penetration calc, damage calc, criticals/deaths calc). A game can last an hour sometimes which means that the total calculations per game can be up to: 48 million. A desync happens when just ONE of the 48 million calculations in one computer is different from any of the others.

The problem is usually not seen AS much (even though it's totally possible) in PVP because most players don't reach the 250 popcap level. But, that doesn't mean they are invincible to desync's.

Even if all computers are great and everyone buys really reliable internet... the internet still isn't always 100% reliable. Personally I've noticed more problems with internet despite paying for higher quality internet during the quarantine because the infrastructure in my area is just not use to the bandwidth of so many people. No matter how much I pay, my internet connection is not always perfect. Sometimes I get many desyncs in one day, sometimes I don't get any for weeks. It really depends on some uncontrollable factors that are not necessarily the mod/patch.

That being said, we have found ways to reduce chances of desyncs. For example, for some really strange reason the COH engine just doesn't do well with call-in units. So in the beta patch which will go live soon, we have less call-in units and switched to buildable versions.
There are also considerations when we design new abilities/fix weapon values. We avoid doing "historically accurate" values which might be insane (for example the rate of fire for machine guns) which can be replicated through other unnoticeable means (for example instead of having a high rate of fire we swap it to a high suppression value with fewer bullets while keeping the sounds and animations the same. So it LOOKS like a lot of bullets but reality it isn't).

All in all, figuring at desyncs is near impossible and most the time it's caused by things the mod itself can't control without making tradeoffs in the complexity/features that make BK good. The game was designed to be played like vanilla company of heroes with much fewer units and weapons available. BK adds more units, bigger scale, bigger everything. There are tradeoffs in stability and features.

The best thing you can do to prevent desyncs is to make sure your computer is capable of running the game, if not reduce the game settings. Also be sure your internet connection is good. More info can be found here: https://www.coh2.org/guides/50098/coh2- ... ance-guide. Check your internet speed and make sure your internet provider isn't cheating you good download/upload speeds! Other than outside of game things, here are some in game tips to reduce chance of desyncs for playing AI games:

1. Don't play BK Fun Mode. The amount of resources the AI gets becomes insane and they start spamming to the point where the game will break down.
2. Don't play 999 Pop Cap. It is recommended at most you play 150 pop cap. Because AI gets accelerated resources even for all difficulty levels, they hit the pop cap pretty quickly.
3. Play victory points. The longer the game goes on the more chances the desyncs will occur.
4. Avoid maps with a lot of destructibles ESPECIALLY too many trees. This doesn't mean unpassable trees, just the ones that can be knocked down. Destructibles really ruin game performance. There's even some maps that are absolutely unplayable even with the best computers unfortunately (example: drachenwald)