So I just pulled it up again to quick bench it. This is with the recent GeForce drivers released last night that are geared towards FH3.
I'm running an i5-4690k / 16 GB DDR3 Ram / 980FTW.
Forza 6: Apex
Condition: Quick race with 16 Le Mans Prototypes on Rio and Abu Dhabi.
Settings: 2560x1440 / Ultra settings / Dynamic res turned off
Results:
100+ frames with a few cars around
75-90 in heavy traffic and bumping
I got it down to 40-50 doing a burnout against traffic and causing a bunch of accidents.
With dyanmic res turned on it stayed pretty much capped at 72 (half the monitor refresh).
Forza Horizon 3
Condition: General play and typical "Horizon"-esque fucking around
Settings: 2560x1440 / Ultra (I think I turned AF to 2x, all AA off, because res) / Frame smoothing I left on I think?
Results: Seemingly anywhere from 30-80+ FPS. Very jumpy, and the jumps are really really noticeable if I don't cap the framerate. There were a few times where the cars were jittery and "teleport-y" with higher or unlocked framerates.
Once I capped the frames at 36 it really seemed to handle it better. But there were *still* times where the game dipped to 30, and I knew it immediately. Very jarring. I may have to play with the frame smoothing / g-sync / v-sync options some more.
There's also been some strange artifacting/glitchy-lighting-flickering... but it's super rare and goes away quickly enough.
So, I think you may want to consider an upgrade, the X1 version, or wait for the benchmark professionals to get their hands on it. FH3 does seem to be quite a bit more demanding (even though I think they have the same system specs on the Windows Store).
I think the discrepancy between Apex and FH3 is due to multiple reasons, one of the biggest being that FH3 is a larger world, constantly loading drivatars / new cars in and out. As opposed to Apex doing single loads and done. I also think FH3 has a noticeably higher ceiling on fidelity. There's definitely a new lighting system in play... because wow. And probably other technologies behind that scenes.
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So who's setting up the GTXf Club??