Can you please provide an apitrace?

thank you for your reply. I'm working on it. I have to get a little into it to understand what I do (I still don't know how to apitrace gothic3 which uses d3d9). ... EDIT: ok, I did it. Now I'm uploading.

@TomadeTT
From what some googling got me to conclude, is that this game has "horrible" performance with CP 1.75 even on Windows machines. I am not saying that DXVK cant fix that, and make it faster than windows, but chances are that.. well.. it is what it is for such a old game.

Few snippits kinda suggested "this old game is single-thread only", and chances are it may actually be faster on older "fewer-but-more-HZ-cores" machines vs "newer-with-many-cores" machines.

https://www.pcgamingwiki.com/wiki/Gothic_3

If you experience problems try Community Patch 1.73 or Community Patch 1.74 instead.[4]

@doitsujin
Traces: http://www.ib-guder.de/Traces_Gothic3_CP1_74_CP1_75.tar.xz

@SveSop: Perhaps there is a margin for improvement and it may be also a benefit for other games/applications. I felt that it is worth to open an issue. Kind regards. Tom

Using D3D9 which indeed is single threaded but unsure why 1.75 would be slower, towards the end of the whole debacle leading to the community patching up the game they resolved numerous memory leaks and performed a number of optimizations plus a few new features were provided through I think it was Spellbound who were developing Arcania at the time.
(That entire development after Piranha split from Jowood is a bit of a mess and a lengthy process of developments and updates as the community got involved in keeping the game updates going.)

What's in the changelog here.
https://upload.worldofplayers.de/files8/Changelog_en.txt

A number of stuff, resource cache changes, multi-threading (Dual core I presume.) maybe something in the ini file that could be tinkered with.

FXAA, higher shadow quality (That's a performance decrease.) and a big number of other additions.

EDIT: 1.75's a big update, bigger than I remembered after finding the English changelog and going through it so you have the usual suspects with the shadow improvements, vegetation shadows and other additions that do affect performance and then there's threading changes and other resource and shader cache attempts that might be better to try and toggle off in the config file with DXVK and letting that handle things instead. :)

There's also the very newest 1.75.14 update which adds a few last adjustments including performance optimizations on top of 1.75 and what that brought over 1.74

It's been a few years (Since 2012 ha ha.) so I don't remember things too clearly myself, hopefully the changelog and it's additions help answer some possible conditions at least for what's changed between the two updates here and maybe if not already applied the newer 1.75.14 update could normalize performance a bit although taking into consideration the added effects and such as a possible performance decrease that is going to be present if using these options.

EDIT:

For "Framework" the changes to multi threading and timing could be something, shader caching could be interfering and the way it rebuilds and handles resource caching until that's done.

Under "Graphics" well everything really some of it might hit performance a bit other stuff could be quite demanding or might even bottleneck the API a bit not sure how well it could translate over to DXVK either, toggling off some of these or comparing as close to 1.74 as possible might be an idea.

Rest of it shouldn't be too complicated.

Some of it might also bottleneck the game engine and it's limits there's tweaks for it but it causes performance to just fall off entirely, would hope they haven't tinkered too much with view distances and drawing of LOD's and such for that reason.

@LordJBeckman Hello. I tried reducing all options to minimum in 1.75. The GPU usage decreases (from 10...30 % to 3...5 %) but the framerate does not increase. One more fact: CPU usage stays below 50% all time when playing (only one core is used). Have a good weekend.

one last comment: I edited the ge3.ini Timer Settings... and BIG surprise: GPU usage increases, FPS increases ... now I look if there are some sideeffects.

;Timer.ThreadSafe - false=off, true=default, use thread safe timer to avoid fast day/night cycles or slowdown issues
Timer.ThreadSafe=false

no issue of dxvk, but of the game/patch 1.75 itself. Changing "Timer.ThreadSafe=true" to "Timer.ThreadSafe=false" solves the problem.