Fire sprite (burning on NPCs) causing very low FPS (BGEE and BG2EE)

Xiathorn

Hi all,

So I posted a reddit post, which I will link here if it's not breaking the rules :
https://www.reddit.com/r/baldursgate/comments/3n3j9u/bgeebg2ee_terrible_performance_with_fire_sprite/

They suggested I post here, so here I am!

When playing both BGEE and BG2EE, my FPS plummets when there are characters 'on fire' - usually as a result of a fireball spell or Melf's Minute Meteors.

As soon as the burning effect disappears, my FPS returns to normal. I run BG on 45fps (because Waukeen's promenade)

Specs :
Windows 7 64bit
i5 2500k @ 3.4Ghz
nVidia GTX680 4GB
8GB DDR3 1333mhz
Driver version : 355.98, running OpenGL 4.5.0 in BG


I've done a check with other games - Witcher 3 on all low (yup, need an upgrade) gives me about 50-60fps, depending on where in the game I am. Most other games give me a comfortable 60fps.

Cerevant

What does the frame rate drop down to? What happens if you leave the frame rate at 30?
Full screen or windowed?
In windowed mode, can you open up task manager and see if the CPU utilization spikes?
Is there any audio playing other than the fireball effect?

Xiathorn

All FPS measured by fraps. For all tests, except explained specifically, the framerate cap was at 45.
Audio is background ambience for Firkraag dungeon, Tazok's room. I tested with both music on and off (I normally play without music, because I'm a heretic).

So, with MMM against a Skeleton Warrior (summoned by me), I dropped from 45FPS to 30FPS. This held at 30FPS while paused, reverting to 45FPS after a few seconds of being unpaused.

With a Fireball scroll against 5 summoned Sword Spiders, I dropped to 20FPS, which held while paused. I could only reproduce this twice - most times, I dropped to 30FPS with the 5 spiders.

With only one Sword Spider left during a 20FPS example (I ended up throwing multiple fireballs for repeat tests, some died), 30FPS returned.

Alt-tabbing from the 20FPS situation while paused results in me returning to 30FPS. I have done this twice only - it's hard to reproduce.

While panning the camera, I sometimes get back to 45FPS - even while paused. Returning the camera to the original position brings me back down to 30FPS (after the alt-tab). When at 20FPS, however, this does not work - I stay at 20FPS (Note - this only happened on one of the 20FPS examples, as I hadn't thought to check it for the first example)

I was also able to replicate with Agannazar's Scorcher, but *not* burning hands. Skull Trap, lightning bolt, etc - no FPS drop. Seems to be fire sprite related?

I currently play in Fullscreen. When playing Windowed, I *did not see* the slowdown. CPU was around 12-20% at all times.

Interestingly, when I saw the fullscreen slowdown (30FPS) and alt-tabbed, I saw Baldur.exe at 48-50% CPU. I watched for a few seconds, and it reverted to 12%. Alt-tabbing back in to the game (which had been paused throughout), I was back at 45FPS. A similar situation happened for the second 20FPS example - 42% CPU, dropped to 12%. Back-in-game meant 30FPS, up from 20FPS.

The audio is the background music for Firkraag's dungeon (I am standing in Tazok's room)


Leaving the framerate at 30FPS means no FPS drop that I can discern, but I suspect I would be able to reproduce the 20FPS drop if I tried hard enough. Sadly I have no way to pause the game when a fireball detonates, or a certain time afterwards, with any granularity, as trying to time the spacebar just right seems to be beyond me, my quake days being long ago

Cerevant

Ok, I'll pass this along to the devs to see if they can spot a bottleneck. Given that 30fps is the intentional, normal frame rate, I don't think this will be a high priority.

Xiathorn

Thanks! I understand it won't be a priority, what with 30FPs being the norm, but it is rather odd regardless.