Extremely low framerate

[Amahula]

So before this comes across as a hate rant, I love promods. Especially Poland looks absolutely amazing.

That being said, while driving in regions like Poland, Germany and especially Spain, framerates go down to ridiculously low numbers. In Bilbao it doesn't go above 35 fps.

My GTX 970 is running at 1540 Mhz and is used 60 - 70% in Bilbao. My CPU isn't used more than 40 - 50%. Video memory doesn't get even close to 3.5 Gb, let alone 4, system RAM not even close to 16 Gb.

The weird thing is that the gpu does hit 100% usage in some areas, but as the framerate goes down, so does gpu usage. So is something else bottlenecking it? I've heard of the game being "unoptimized", but what is holding it back?

Anyway, don't take this as hate. Bilbao is beautiful. Just wanted to know if anybody else with a, if I may say so myself, powerful PC has these issues.

My Specs may it help with an answer: (I'm guessing this isn't low tech)
Asrock b85 pro4 Mobo
i5 4690k @ 4.4 Ghz (+212 EVO)
4 x 4 Gb 1600 Mhz ddr3 Kingston RAM
MSI GTX 970 @ +186 Mhz Base +415 Mhz Memory
OS (including mods): 240 Gb Kingston SSD
Steam (base game): 500 Gb Crusial SSD

PS: I'm running two visual mods: IWR6 and HD roads, but these framerate issues appear without these mods as well, so if they contribute to the problem, it does so very little.

[Callipso]

Bilbao and Barcelona have low frame rates to the number of draw calls that are being requested by the game. currently the devs are trying their best to optimize them better. I have a computer with a SLI set up and 6 core processor and still the rates are low in many areas with large numbers of draw calls, so your not alone and many have also expressed their dissatisfaction with the frame rates of these cities. Trust me the devs are working on the problem as best they can

[ETS2-User]

I've heard of the game being "unoptimized", but what is holding it back?

One simple answer: The old DirectX 9 engine. We hope for a new engine in the coming ETS2 updates.