There was a vocal minority of players who were pretty upset when the old MSAA options were removed in patch 6.0 in favor of visually inferior (in most cases) post-processing AA options. Heck, Blizzard even wrote a technical blog explaining why they decided to remove MSAA. In short, their reasoning behind its removal was because it caused too big of a performance hit.
This wasn’t surprising since MSAA is very performance unfriendly, especially if you run the game at a higher resolution. Blizzard has always aimed for WoW to work on the lowest common denominator of PC hardware, but many argued there was no reason to take away the other AA options from people who do have the hardware to utilize it. I personally have a GTX 780 video card which is overkill by about 5x for WoW, but it is nice to be able to turn on every single option to max and still run the game at 60+ fps at all times.
The good news is that Blizzard listened and they have re-implemented MSAA as an option in patch 6.1. They’ve also added two new options, both even more performance hungry than MSAA.
Update: Since this article was written, Blizzard has added support for post-process AA (FXAA or CMAA) while running MSAA, under advanced graphical options.
Anti-aliasing options at a glance
These are listed from lowest to highest in terms of their performance hit (same order they are listed in the game options).
- FXAA Low: Short for “Fast Approximate Anti-Aliasing,” this is a low-cost AA method that searches the whole image for edges and attempts to smooth out jagged edges. The problem with FXAA is it can also detect edges on textures which causes a slight blurring effect.
- FXAA High: Same as FXAA Low but does a better job for a slightly larger performance hit. It blurs the image noticeably less than the Low option.
- CMAA: Short for “Conservative Morphological Anti-Aliasing,” this works similarly to FXAA except it is a lot more conservative as its name implies. It doesn’t blur the image nearly as much and does a better job at only smoothing out geometric edges rather than the entire image.
- MSAA 2x: Short for “Multisample Anti-Aliasing,” this is the traditional AA method that has been around for a long time. It essentially renders part of the image at a higher resolution and then downscales it back to normal size to remove jagged edges on geometry. This is a gross oversimplification, but I am not writing a paper here. What you need to know is that MSAA is computationally expensive and very hungry for memory and memory bandwidth. The end result is very clean edges on geometry, but since it doesn’t affect transparent textures it has no effect on things like foliage in WoW (whereas the 3 previously mentioned AA methods do).
- MSAA 4x: Same as MSAA 2x but it samples the image even higher, resulting in even smoother edges.
- MSAA 8x: This is where MSAA starts to reach diminishing returns. There is only a very slight visible difference between 4x and 8x, a much smaller improvement compared to 2x -> 4x. I believe 4x to be the sweet spot.
- SSAA 2x: Short for “Supersample Anti-Aliasing,” I like to call this option “screenshot mode.” It can best be described as rendering the image at double the normal resolution and then scaling it back down to normal size. It is a brute force approach, is extremely expensive, but the resulting image quality is outstanding. The benefit of SSAA extends beyond removing jagged edges as it also increases texture quality.
- SSAA 2x + CMAA: The same as SSAA 2x, but with an added kick of CMAA to help clean up any of the more problematic edges. Absolute murder to your FPS.
DirectX 9 vs DirectX 11
All of the above AA methods work when running the game in DirectX 11 mode (found under advanced options), but if you have an older video card that only supports DirectX 9 then your only AA options are FXAA Low, FXAA High, and SSAA 2x. I find it odd that MSAA is no longer available under DX9 since it used to be, but it’s possible Blizzard is using a new method which is unsupported in DX9. Any video card from the last 4 years or so should support DX11.
Anti-Aliasing Comparison — Edges
If you’re having trouble seeing differences between the different AA modes in the following comparisons, try sitting back farther from your monitor and see if it makes a difference.
This is a worst case scenario. Stairs in Stormwind viewed on a slight angle. You can see here why I’m not a big fan of FXAA (especially the Low setting). All it looks like to me is it took the image and blurred it. FXAA High is a bit better and at least begins to remove the aliasing effect. CMAA really does quite a nice job considering how low cost it is to run.
You may think there’s not much difference between CMAA and MSAA, and you’d be right for a still image like this. MSAA’s main advantage is that it looks better in motion. With CMAA there can be “crawling” pixels on the edges of objects during movement. This is because a post-processing AA like CMAA dynamically applies its AA to every frame, whereas MSAA applies itself to everything without prejudice, making it more consistent.
The SSAA 2x + CMAA option is simply in another league. Not only are jaggies removed but the texture on the stairs even looks better.
Anti-Aliasing Comparison — Foliage and Nameplates
Again, FXAA is just a blur filter to my eyes. CMAA is perhaps a little bit too conservative (but I’d rather have that than blurring). Here is where we see MSAA’s weakness. It has zero effect on transparent textures like this. I really wish there was a MSAA 4x + CMAA option, but I’m not sure if that’s even possible (update: There is now in advanced graphic options). SSAA predictably looks amazing.
This type of anti-aliasing also applies to nameplates, as you can see below (compare the more distant nameplates):
The FXAA blurring is really troublesome here for me, just look at the pandas. MSAA again has no effect on the nameplates, and SSAA allows you to have legible nameplates at a greater distance.
Anti-Aliasing Comparison — Textures
As you can see, FXAA ends up blurring textures quite a bit. CMAA blurs the Alliance logo only ever so slightly. MSAA has zero effect on game textures. SSAA ends up improving the quality of the textures.
Unfortunately, I can’t really delve too far into this because I don’t have multiple video cards to test. On my GTX 780, everything from FXAA to MSAA 8x has about the same performance. Once I enable SSAA it cuts my frame rate in half, and since I am already running 2560×1440 at Ultra settings, it’s too much of a hit for gameplay. I like to keep my FPS at 60+.
On lower performance cards, you’ll absolutely see a difference. Your best bet is to just test things out yourself and see what the frame rate hit is. All of these AA settings can be changed without exiting the game. I’d also suggest trying both Windowed (Fullscreen) and Fullscreen modes. You might find drastic FPS differences between the two options.
My guess is CMAA will be the go to choice for the average player. I’d be extremely curious to see if anyone has a rig that can do the SSAA options at 60+ fps. Perhaps WoW finally has a use for SLI (dual video cards)?
Even though it doesn’t affect transparent textures, MSAA is my preferred choice outside of SSAA screenshot mode. What I like about MSAA is it looks better in motion. I wish I could do a video to demonstrate this, but the video compression on somewhere like YouTube would make it impossible to properly compare.
The only situation I would ever recommend FXAA High is if you’re A) stuck on a DX9 video card and B) run a very low resolution, like 1366×768 on a laptop. In that case, a little bit of blurring may be preferential to Jaggy-Fest ’15. As for FXAA Low, I don’t think I’d use it in any situation. No AA is better if you ask me.
I know this had nothing to do with hunters and is probably a little bit too much techno mumbo jumbo for most people reading this (I’m shocked you got this far), but I’m a bit of a graphics quality junkie. The new AA options were actually one of my most anticipated things from the patch. It sounds silly but there it is! Hopefully you learned something.
Check out these unmodified screenshots of SSAA in action. Zoom to 100% and just try to find a jaggy edge somewhere. Good luck.