Strange performance issue in FFXII

[zniffynifty]

Hi there,

I've been using PCSX2 Playground 1.0.0395 to play FFXII for a few weeks now, and I must say it's fun beyond imagining. You guys do really great work - I have all the respect in the world for programmers who work with low-level code, and it looks like you've optimized the hell out of this.

That being said, there is one issue in FFXII that stands out above the others, and I think it may be a bug - when one character performs a specific attack, I see a slowdown from >50 FPS to <15 FPS. I want to point out that I never get a slowdown this intense anywhere else in the game - perhaps 40fps during intense battles, but never this low.

Specifically, when the character Basch uses the level 3 Mist Quickening "Flame Purge", he conjures up twelve flaming swords that impale the target and then shatter. The moment the swords shatter, the game slows down to <15 FPS; my CPU load also jumps to 100%. When the attack animation finally ends, the FPS is back to normal.

Now my initial hunch is that when the swords shatter, the game is faced with many more polygons than there were before, and this stresses the CPU. However, it seems that nowhere else in the game does it slow down by this much.. and it makes me suspicious that something else is at fault here.

I can do my best to provide any additional info you need if you're interested in helping resolve this issue. For now, here are my hardware specs and configuration.

CPU: Intel C2Q Q9550, stock (2.83GHz)
Video: NVidia 8800 GT
Gfx plugin: Gsdx 890 0.1.14 (SSE4)

Thanks a lot!

PS: For those interested in figuring out this problem, I wanted to let you know that I'm very interested in how PCSX2 actually works, so I'd appreciate it if your explanations erred toward the technical.

This post has two attachments - screenshots before and after the slowdown.

   

   

[Nneeve]

It seems like it could be caused by GSDX (due to the large CPU % number shown on GSDX's titlebar). Try using an older version of GSDX (such as 0.1.7 or 0.1.4, they can be much faster in some games/moments) or the DX10 renderer (if available on your system).

[jap_yuuki]

well, for basch mist slowdown case, i think that's the way it is<i got only 10fps for that scene>.

[Wohlrajh]

Specifically, when the character Basch uses the level 3 Mist Quickening "Flame Purge", he conjures up twelve flaming swords that impale the target and then shatter. The moment the swords shatter, the game slows down to <15 FPS; my CPU load also jumps to 100%. When the attack animation finally ends, the FPS is back to normal.

Yep same problem here, my FPS is always capped to 60 FPS elsewhere but when I use level 3 mist for Basch, the FPS always drop to ~20 FPS, perhaps a GSdx problem as you say. I think FF12 is really CPU and GPU demanding sometimes. I also noticed some drops, especially on the last espers fights when there is some bloom effect during the fights but the FPS drop is accpetable for me so I didn't care but for Basch mist the FPS drop is indeed huge xD

[Zeydlitz]

If it's GSDX trouble you could quicly check it by switching to ZeroGS. As I recall, at last versions of pcsx2 you could do it at run-time. But anyway save before.

[rama]

Try an older version of GSdx (1.1.7 will be good). It has a hack enabled which I think is needed in that spot.
And yes, it's a GSdx slowdown

[kebrus]

this is definitely a problem with gsdx, for example with odin's sphere (a pretty much 2d game) it's unplayable with gsdx, because somehow it puts the gpu at 99% all the time, droping my fps to ~50 which sucks, fortunately zerogs runs great with that game

[zniffynifty]

Wow. I used the older version of GSdx and it worked! Thanks!!

I am wondering why the newer GSdx breaks things - does it have some newer features that don't work with FFXII? Will the old version have any noticeable differences from the new version?

Also, will I notice any slowdowns because the older version of GSdx doesn't support the SSE4 instruction set?'

Thanks again.