STALKER 2's latest update expands its A-Life NPC simulation bubble, seemingly without a scary performance tax

STALKER 2: Heart of Chornobyl has a new update out, 2.1, which builds on the excellent 2.0 patch by upgrading that most beloved and contentious of STALKER series features: the A-Life system that governs simulated NPC behavior. With the 2.1 update. It's now possible to whack up the distance at which A-Life NPCs (who, unlike scripted characters, will wander around, fight others over faction turf, and sometimes hunker down for a campfire-side guitar sesh) are visualised, while audio tweaks can make these unplanned shootouts audible from further away. The effect, in theory, is a better sense of the Zone's inhabitants going about their bang-banging business, even if Mr. Main Character here isn't close by.

Both the updated game and the accompanying blog post warn that cranking this A-Life bubble up beyond the lowest, default 'Recommended' setting may have adverse effects, ranging from lower framerates to "story quest instability" and crashes. Fearing a return to STALKER 2's bug-ridden early days, I tried out the new A-Life distance options on the RPS test rig, and found they're not actually that perilous – though they might do strange things with binoculars.

To judge the performance effect, I ran the rig's RTX 4060 at 1080p, with Quality-level DLSS and the High preset - save for having the draw distance setting on Epic, to maximise the potential visualisation. Walking through an open, A-Life-ripe patch of the Zone produced a 93fps average on Recommended, which remained unchanged on the Extended setting, before barely dropping to 91fps on the Highly Extended, Maximum and Dynamic settings. Well that's not so bad! The warnings made it sound like the bigger options would ignite the air around my graphics card and brainwarp quest NPCs into thinking they were in Barbie Horse Ride & Rescue (available now on Steam). 2fps? That's nothing. Nothing.

Granted, results may vary depending on your PC specs; the RTX 4060 isn't especially potent but it was backed up by a good CPU and a healthy 32GB of RAM, which likely helped handle the extra computations required for a wider sprawl of distant gunfights. To get a fuller picture, I did try a different approach, leaving ground level to claim a lofty concrete vantage point and- god dammit, recently added fog effects.

That's better.

Still, the Zone's unknowable RNG calculations were not kind, and after several minutes of fruitless waiting I returned to run more tests on terra firma.

I ultimately didn't find anything else that would suggest an unacceptable risk of performance loss or instability, though I did discover one quirk of the new system: in addition to render distance, your choice of A-Life setting also appears to influence the range at which faction markers show up on binoculars.

More strangely, selecting Maximum A-Life also seems to… increase the zoom of binoculars? As you can see in those two shots, which were snapped from the same position. I guess it's a bug but hey, if GSC are telling me I can get better NPC simulation and a magnification upgrade for the low, low price of two frames per second, I'll take that deal.

STALKER 2 2.1 is out now for everyone. Besides the A-Life distance gubbins, it also adds the ability to tag along with roaming fellow stalkers, turning them into mobile fast travel stations - though, in keeping with the notion that NPCs don't actually give a toss about you, they'll only warp you to places that their specific patrol route was passing anyway.