Recently, I did an article and video graphics analysis comparing the Playstation 4 and PC versions of AC4. During both the article and video I spouted on about an upcoming patch for AC4 which would enable Nvidia’s Hardware Physx for the PC, Well, now the patch is here and Assassin’s Creed 4 has been given an update allowing users to enable Nvida’s Hardware PhysX on the title. So let’s explore what this patch does and was it worth the wait.
Enabling Nvidia Hardware PhysX for Assassin’s Creed 4 Black Flag (AC4)
Firstly – let’s discuss how you enable Nvidia’s hardware PhysX for Assassin’s Creed 4 Black Flag. You require a Nvidia graphics card (hardware PhysX doesn’t work with AMD Radeon / any other card) which supports Hardware Physx, and also download the patch for AC4. The GPU you require in theory could be anything after the 8xxx series (for instance, the 8800 GTX) but you’ll need something more modern to enjoy the game at decent frame rate, graphic settings and with Nvidia’s hardware PhysX enabled. The patch is downloaded automatically via your digital platform of choice (either Steam or Uplay).
As for the graphics card – depending upon the levels of graphical detail and resolution, be warned that Nvidia’s hardware Physx can take quite the toll on performance. Let’s see if that’s the case for AC4. We’ll be running the game at 1920×1080 (1080P) and with all of the graphic options set to their highest (but with MSAA 2x). These are exactly the same settings used in the Playstation 4 vs PC Black Flag comparison I did a short while ago, so if you want to compare videos / screenshots of the PS4 version of the title, then you’re more than welcome to. Article here.
Click for larger image
You’ll no doubt have keenly observed that the option ‘PhysX particles’ have three settings: off, low and high. All of my own tests were conducted with the highest setting (high) enabled, or with PhysX disabled as a comparison. Nvidia’s hardware PhysX can perform a variety of different tasks, including animating various debris, cloths and other fabrics to look and flow more realistically. For the most part, Assassin’s Creed 4: Black Flag when patched benefits from much more realistic smoke and particle effects. Smoke effects linger for a moment, and are blown with the wind, and are affected by the movements of your character. Interestingly, Nvidia’s Hardware PhysX can be enabled and disabled from within the games graphical menu and doesn’t require a reboot / quitting out. you can easily walk up to various camp fires, shoot your pistols and so on and toggle the effect to see the difference.
What doesn’t hardware PhysX do for Black Flag
Firstly – let’s get the bad stuff out of the way first. There is very little difference in terms of debris blowing around in the street, leaves from trees, and extra effects on clothing. I’d initially hoped upon hearing about the AC4 Physx Patch that these effects would be included – and I’ve a feeling would help the ship battles feel even more epic. There are certainly more particles flying about, for example from the muzzle of the guns, but I was really hoping to see litter blowing around the streets. Likely there are reasons behind this – it would have been extremely difficult to simply patch that in in terms of time, and secondly it likely would have eaten GPU performance alive in such an open world setting as Black Flag.
What plunder it does bring for AC4 Black Flag
The good news is that it makes a noticeable difference around camp fires, pistols, smoke bombs, swamp marshes and pretty much anything else that emanates particles. Smoke washes around your character, and when you do the ‘shooting from the hip’ style combos with both pistols, it looks pretty damn impressive. You could be forgiven for simply at first glance assuming that all you get is a bunch of extra smoke and that is your lot. But this isn’t quite true. Assassin’s Creed 4 already looks damn pretty, but the smoke in some cases can look a little ‘samey’, lacking variety and changes in density. Hardware PhysX changes this rather drastically, with the initial wave of smoke from say a smoke bomb behind far thicker than the remnants. There are clear and distinguishable waves of smoke, rather than a simple haze effect that software PhysX produces. 
Is this game changing and really ‘The Way It’s Meant to be Played?” as Nvidia claims? Well, I won’t lie – on some effects (the sea battles in particular during heavy rain) you’ll probably not notice if you’re busy dodging cannon fire. But if you’re simply walking about and exploring the games world, you’ll quickly start noticing the little touches. More over, after playing with them on for long enough, you do miss them when they are disabled. 
Performance impact on AC4 with HardwarePhysX enabled
I did some testing on with and without Nvidia’s hardware Physx and did notice a very slight drop in CPU utilization when the hardware Physx were enabled. However, it could have well been within the margin of error (perhaps 1 or 2 percent on one of the eight threads of my Haswell 4770K). GPU performance however was certainly hit hard. PhysX is notorious for doing a number on your GPU, but AC4 isn’t too bad at all. On my GTX 680 I noticed a drop of just a few frames per second with hardware PhysX turned on. How much of a drop? Using a few sections of being on board ship and simply firing cannons, or indeed during walking around town and using items like smoke bombs there was very little performance drop. During the shooting range, I ran an average FPS count and lost 5 FPS with PhysX on the highest settings. The motto of the story is that you’ll be losing single digital percentage of performance and so it shouldn’t be a problem for most medium to high end Nvidia GPU’s to turn on the feature.
High Bitrate Video
Aside from the YouTube video (which shows tons of different effects and I’d highly recommend you watch it) I’ve also made a few small snippets available to download here.
