Performance.

[skillfultree]

I feel like 1.2 has taken hit to performance. Playing a few custom battles I get a lot of stutter from units (though oddly not the camera). I tried a few Rome vs Suebi siege battles and the stutter is pretty constant, though trying other factions my performance is fine. I only have around 7 vs 12 units. I have a GTX 1070 and i5 2500k.

[Fequois]

I haven't noticed any difference in performance, but to be fair, I have a pretty powerful machine too (i7 6700k, Titan X (Pascal)). What I did see, however, is that when I increased the settings even further, the stutter I've always had in Rome 2 started disappearing. Perhaps the shadows are now rendered by the GPU instead of the CPU or something stupid like that, I'm not sure.

[Kolaris8472]

Yep there are a few settings that when put on the highest two options will switch over to GPU. I'd try that since stutter without camera choppiness probably means it's a CPU bottleneck.

[Fequois]

@Kolaris, do you know which ones do that?

[Kolaris8472]

Should be Shadows, Particles, Building Detail, and Unit Detail.

[Dresden]

You can see in the FAQ this used to get asked alot, its one of the questions there - http://www.twcenter.net/forums/showt...-et-Impera-FAQ

That answer there was from a user a long time ago but it probably still applies. For some reason, some settings are actually better at higher levels for performance.

[Grigal]

Hey guys, thx for the great mod first of all.
I also noticed stutters in battles sometimes, since the introduction of 1.2 DEI: everything just freezes for a short period and I cannot click anything or give orders however fps is high and I can move my camera freely. I think it has something to do how AI handles units that have ammunition. I ran a few custom battles to test it. First of all I made a custom match vs AI having many no-ammunition units (like pikes or hoplites). It didnt stutter at all. After that I made a match vs AI having many units (melee) with ammunition and it started stuttering at the point where PC started giving attack orders to his units that have ammunition (melees started acting pretty much like peltlasts since the introduction of 1.2 - they shoot all the ammo before engaging - except they dont have "skirmisher mode", like shoot and run back if chased). While my pc is not fast at all but it handles big sieges well and Im using GEM and other graphics mods. But when it comes to PC giving orders to his javelins-armed units I experience stuttering (not all the time, just sometimes), it is gone after some time (usually when the battle is in close quarters or when PC is out of ammo). I'm not saying it's a bug or anything, just thinking that 1.2 started taxing old PCs like mine alot more than 1.1 probably. But I may be wrong. My pc is i5, 8GB ram, GTX 650Ti.
PS: My fps is around 40-60 even during the stutters. I tried the solution for stutters in the FAQ thread but it didnt work for me. I guess it's just a slow CPU issue. Sorry for the language.

[KAM 2150]

1.2 also has a lot more variety of textures among units etc and that can affect performance too.

[Fequois]

I feel fairly certain that DEI does not cause this issue because it's exactly the same without. I'm 99% sure most stuttering (on modern machines) is due to unit blobbing and pathfinding, particularly in settlements. The game engine just can't handle it.

A workaround is to play with smaller unit sizes and/or avoid blobbing your units.

[Dresden]

There were some posts about this on the Attila forums also - so the issue was never really addressed. It has to due with ladders, siege pathfinding and unit stuttering in those situations.

[Augustusng]

Yep, the stuttering is mostly what Fequois and Dresden are saying. It's a way the game slows down without actually lowering your FPS. It's almost a clever optimization trick... or it would be, if it wasn't so noticeable.

[Causeless]

Yep, the stuttering is mostly what Fequois and Dresden are saying. It's a way the game slows down without actually lowering your FPS. It's almost a clever optimization trick... or it would be, if it wasn't so noticeable.

It's not really an optimization trick as much as it is a consequence of the engine architecture. I've written a game loop architecture that does the same thing - it's fairly common with RTS games, especially multiplayer networked RTS games which generally run at a fixed tick-rate.

For a multitude of architectural design reasons, the game simulation runs at a fixed tick-rate. The campaign runs at 10fps. I'm not certain about battles but they presumably run at a similar rate.

In most games, especially shooters, having simulation code run at the same FPS as rendering isn't a big deal. It doesn't matter too much. If the frame-rate runs at 30fps instead of 60fps, the simulation might change slightly but it's not game-breaking. There's slight differences in physical simulations etc, but usually it's not a critical flaw (unless framerates get very, very low).

However, in RTS games, having the simulation tick-rate be tied at all to the render FPS is a huge issue. These slight behavioral changes have very large consequences when it comes to battle replays and multiplayer, especially, where the tiniest synchronization flaw can result in huge changes (ala butterfly-effect). This is why battle replays act differently when you try playing them with an older version of the game.

Anyways, because of this, the simulation code runs at a fixed rate. If your PC is capable of running at 120fps, the camera might move smoother but the underlying simulation runs at the same speed as before. If your PC is only capable of running at 5fps though... then the simulation cannot keep up.

In an FPS, the game will just skip frames. It'll run at 5fps and things will seem juddery, but the game will make up for the discrepancy by making everything in the game move a further distance per tick. However, due to the differences this causes in the simulation, Total War cannot do this, so it must slow the entire simulation down to the same rate that the game can simulate it at.

Also, because your PC has a separate CPU and GPU, it means that your GPU might easily be able to render at 60fps while the CPU is struggling to run the simulation code. In this case, there's no point in slowing down the GPU and render framerate to match the CPU, so the game still looks smooth as everything slows down.

The point is, it's not really a "trick" that they coded in to handle low FPS. It's a necessary consequence of the game's technical requirements and architectural design. If the game just limited your render FPS to match the simulation FPS, the entire game would now be juddering but it's wouldn't actually speed up the simulation at all.

[Fequois]

@Causeless, that was a very interesting read so thanks for that. I knew about the so-called tickrate, but I never really thought about the last thing you said: that the GPU and CPU aren't necessarily synchronised.

[daimyo21]

Thanks for the explanation Causeless. If anyone wants to prove his point, run the game in single-core mode and thats what you get, camera and simulation matched at 1-3 fps. I must have tried everything to mitigate this issue.. I have a better CPU today and havent tried to see if it can handle what previously would lag. I wonder if this is every fixable through modding or unofficial patching?

[Augustusng]

Fair enough, thanks for the explanation!

[Dresden]

@Causeless very interesting, thanks for posting that.

[NeptuneUK]

My system runs better on medium settings than low... which is odd. I have actually noticed an INCREASE in performance recently, though I don't know why that is...

[KAM 2150]

Mthat is because the higher the settings, everything is more evenly distributed between you CPU and GPU. The lower the settings, the more stuff is being forced on just CPU.

[Little Legionaire]

IMO, i5 2500K is good cpu unit with a remarkable OC capabilities (i used one for five years) but when it comes to combine it's performance with GTX 1070 "may" cause GPU bottleneck.