I have the Steam version of Divinity II and I was wondering if there will be any changes besides Developers Mode to the GOG release. The game runs with this weird lag/stuttering that many have complained about. By default the game was locked at 30 FPS and still runs with this stuttering even on high level PC rigs despite any changes to the graphical options. I'm just wondering if anyone has any information about the technical differences. I was wondering if the game ran like that due as a result of the DRM in the Steam release. I'm aware the DRM was eventually removed but I'm not sure if any remnants of it is still affecting the game. I'd like the purchase the Anthology so I appreciate any feedback :)

You can change or remove the frame rate cap in the options (before the second patch it was locked at 30).

I don't think there were any changes in D2:DC from DKS, aside from the Developer Mode, at least none significant enough to be worth mentioning (that I've seen, anyway).
Of the people who reported running into similar issues, I don't recall Steam coming up more than expected (also, you can start the game without the Steam client running; even before the DRM was removed it just used Securom, not Steam).

You may have already gone through them, but there are a few topics in the Larian forum with suggestions.

Try setting Distance Rendering to low and enable time slice shadows.

Check out the topic cant get over 7fps and the links it contains, and maybe the D2:ED topics below.

Choppy game - possible fix

For people with stuttering graphics

Thanks for the prompt reply. I have one other question. It's stated on the website that Divinity Anthology includes "unique items for the upcoming Divinity: Dragon Commander and Divinity: Original Sin" I noticed that this is mentioned for the retail release of the game. Will this be included if one purchases the digital GOG version of the anthology as well? Also what about those who already own the game on other platforms like Steam. Will the unique items be available for early adopters or does the game need to be bought again to acquire them?

The DLC item codes for D:DC and D:OS are only in the retail version of the anthology. It was actually a distributor for the boxed version that got the DLC added in the first place (see Swen Vincke's reply to a comment in the blog post Hatching the Anthology).

There was a Chinese New Year promo offer for Dragon Commander DLC early this year (forum announcement). The webpage is still up, so you can try submitting your email address to get in on the deal (as long as you don't mind silver instead of gold). I have not gotten any announcements from signing up (despite leaving the option checked to get updates), so you don't have to worry about getting on any mailing lists, etc.

There may be other opportunities for DLC bonuses as the releases for D:DC and D:OS get closer, or presumably with certain releases.