The new Fallout 4: Far Harbor DLC released recently, with some PlayStation 4 owners claiming that this expanded area has substantial performance issues not found in the main game. Based on just a two-hour sample of this new content, criticisms surrounding poor frame-rates on PS4 are definitely warranted. As of patch 1.6, venturing out into the woodlands in the new area can see the game running at a baseline 20fps - or worse. As things stand, PS4's current performance profile sees the Far Harbor region present one of the most sluggish regions in the game, while Xbox One consistently runs at a higher refresh.

The cause and effect is obvious. Fallout 4 usually targets 30fps on console, but a more aggressive use of a volumetric fog effect across Far Harbor's island triggers PS4 to cap this refresh at 20fps - with dips to 15fps at its extremes. It's a thick layer of alpha transparency effects causing the issue, making any real-time targeting hugely difficult, something we noticed during an early woodland mission with ally Old Longfellow. Xbox One suffers fluctuations up and down the scale and is far from ideal, but it's certainly Sony's machine that struggles most right now.

This lock to a sub-par refresh is unusual, but we've seen something similar happen before. We saw the same kind of impact to performance in The Witcher 3's demanding Crookback Bog area, perhaps suggesting that a form of double-buffer v-sync is in play on the PS4 release. In that case, it was another effects-heavy spot that capped performance to 20fps on PS4, while in Fallout 4's case it goes one worse - producing a 15fps lock at its worst points.

This content is hosted on an external platform, which will only display it if you accept targeting cookies. Please enable cookies to view. Manage cookie settings A look at Fallout 4: Far Harbor's performance on PS4 and Xbox One - in which Sony's machine runs at a near-constant 20fps (and under).

Curiously, the double-buffer v-sync effect doesn't manifest to the same extreme on Xbox One, and with its performance running the gamut between 20-30fps, it's smoother to play overall - though still some way off the locked 30fps the developer is aiming for. Xbox One has issues of its own too: we experienced a software lock-up while playing missions required to enable this expansion, plus the stuttering issues that have marred the experience since launch still have not been addressed. We've had fewer issues with PS4 in this regard fortunately, where this stuttering is still far less prevalent.

Fallout 4 has previous history with frame-rate problems, of course, reaching its nadir around the Corvega Factory where we encountered similar sub-20fps points in playback. However, Far Harbor is in a more worrying condition right now: this is the largest region added to the game so far, and yet much of it is covered in this performance-sapping fog effect. It's not a one-off either: while interior spots and towns run close to 30fps, anything outdoors operates at this distracting level of performance.

Based on our testing, PS4 owners are right to be more frustrated with the performance level of the expansion. It's especially glaring in this case, given that 20fps is essentially the frame-rate ceiling in these areas, and the problems are only amplified when any real action kicks off. Fortunately Bethesda promises an imminent patch to fix it, and so we'll see if Far Harbor's fortunes change for the better in the coming days.