What does FXAA in the options menu do? It is a checkbox, you either check it or leave it unchecked. Thanks for any help.

If you think of it as Hardware Accelerated AA, then you are not too far off the mark.

Here is a detailed explanation

http://www.codinghorror.com/blog/2011/12/fast-approximate-anti-aliasing-fxaa.html

Some video cards and systems do well with this checked, some do not. I have not used it myself as I am old enough to not care about AA that much. Losing close focus depth of field as we age does have some advantages. So, I don't know if you have to set a corresponding setting in your video card's control panel, something else I don't let run on my system as I let games set AA and AF and whatnot.

There are however better reasons than just getting old and blind to care less about it.

Games these days have many effects that often cause a reduction of the stair effect on lines. Take the bloom effect for instance. It softens highlights and washes them out and reduces the stair effect at those highlights. Depth of field simulation, fog and weather effects indirectly reduce stair effects by reducing the overall range of the colour palette. Water effects like reflection and refraction constantly produce movements and make it impossible to spot a stair effect. It is similar with heat blur effects. In short, the more effects there are, the less we are able to notice stairs in lines. What remains can get handled by a combination of a low AA and FXAA setting.

Thank you for the link. I appreciate it!

So is FXAA better than AA or just a a faster almost as good version?

AA is the true anti-aliasing algorithm. The cost of AA gets high quick with each step (2x, 4x, 8x, 12x, 16x), while the gain gets smaller.

FXAA is an approximation of AA. It filters the final image. Its effect is close to AA, but it costs less than true AA. Because it is an approximation can it not replace true AA in terms of image quality. It is however faster than AA.

I use AA until most of the stair effects are gone and without trading too much FPS for quality, and then let FXAA take care of the rest.

So you can have both enabled at the same time? What about that blurry image comment for FXAA?

aha... I always wondered myself. thanks.

Yes, you can. Best is to test it.

Because FXAA is only an approximation and works like a filter can it cause blurriness.

For example, when you want something to look like it has got a stair effect and put it into a texture, will AA not touch it, but FXAA will. Players will more likely see this as a good thing, while artists will tend to see it as bad or incorrect.

Everyone's results are different. If FXAA works well on your system, then use it. But as other's have posted, true AA is better for the heavy lifting. Say up to 2X or 4X with AA, add FXAA if needed or desired instead of going to 8X 16X. Or, you might just prefer 4X or 8X straight AA. In addition, sometimes it is better to use the GPU's control panel and force AA there, and sometimes it is better to use the in game setting instead. One will perform better than others. However, I never let the GPU control panel software load myself and always use in game settings.

As always, you need to balance game performance with visual quality. Only you can determine if a change is for the better or worse on your rig to your eyes.

Basically before the HD texture packs i just had the max AA but now i am considering lowering the actual AA and applying FXAA as there is some stuttering due to the textures, i think.

Before the HD texture pack I used 8x AA. After the HD pack, in some outdoor areas, I started dropping fps, so I switched to 4x AA and FXAA. I like the look and performance is better.

If you have got an Nvidia card then you can enable transparency anti-aliasing, too.

Some textures have transparent parts like all the grass and bushes. Transparency anti-aliasing takes care of the stair effect along all the little branches and leafs.

You need to enable it in your driver and in the SkyrimPrefs.ini file. You find this file in your home directory under

Documents\My Games\Skyrim\

Search for the display section and add (or change, if it already exists) the following to it:

[display]...bTransparencyMultisampling=1

I'm in my 40s, but I still pick out jaggies. Although, I've heard others say FXAA/MLAA makes textures blurry... but I need a screenshot comparison to notice so I guess to me textures are already blurry.

In my own experience, multisampling and transparency AA have a pretty severe effect on performance. FXAA and SMAA provide more or less free transparency antialiasing.

I have all the in-game antialiasing settings turned off, with the InjectSMAA hack installed. http://mrhaandi.blogspot.com/p/injectsmaa.html They say it offers similar performance to FXAA, but without the texture blurring.

I've heard SGSSAA is supposed to be a fast transparency option, but I've never tried it myself.

Also, the MSAA w/ transparency settings can be changed from the nvidia control panel if you have an nvidia card, without the need to edit a config file.

I already had once a conversation with someone who believed in SGSSAA being a good thing. It is however only a bug in some versions of the Nvidia driver and should be treated as such. Even Nvidia engineers take a distance to it and so should everyone else. If you cannot spare a few frames then you are free to trade true AA with anything you see fit of course.

I have ambient occlusion enabled... Wherever two surfaces intersect does it create a line (law of math). Ambient occlusion will shade these intersection lines and any stair effect gets reduced in its strength as a result of this. It is another effect that reduces the overall need for anti-aliasing. And all those extra ambient shadows look great, too.

It is better to enable all effects and thereby to keep AA at a minimum, before one turns everything off and then to treat the image with onions, LSD and fabric softener.