Why does Anti-Aliasing always bring my video card down?

Mine's a HD 3650 Mobility. I woulda thought it could handle at least some decent anti-aliasing, but no. It halves the frame-rate, and then some.

What the hell do I have to do to get some decent smoothing?

 

AA is very GPU intensive and your graphics card isn't that powerful.

Using higher resolutions results in less aliasing so try that.

 

Well, fill-rate and video memory bandwidth greatly impact anti-aliasing performance.

Unfortunately, these 2 items have sort of taken a back seat to emphasis on shaders alone when it comes to modern laptop cards (especially mid-range ones.)

 

turn off V-sync as well it helps =)

 

You know how much a decrease there is in performance by upping the rez? Well, adding 2x AA essentially adds another 'layer' of resolution, and the screen is actually rendered twice. This is why it is so taxing on the GPU.

From Wikipedia:

 

Yeah AA really tones down performance and is very reliant on the GPU's refill rate, which as Tony said, has taken a secondary place when compared to shaders and clock speeds on most notebook GPUs.

 

Sort of. You are describing multi-sampling, but your quote is for super-sampling which is different than multi-sampling.

IE--2X AA multi sampling an 1280x720 image, has to render it twice.

but 2X AA Super sampling an 1280x720 image must render @ 2560x1440 , then downsample.

Generally, supersampling has a much larger performance hit than multisampling, but gives better (visual) results.

 

Ahh, okay, thanks!

 

Yeah, one time I believed my card could handle some AA...I got nice image quality, but the lag was unbearable. (Maybe because I tried it with Crysis...)

Hopefully I'll be able to enjoy it once I get my new laptop.

 

Rule of thumb: If you get 60+ FPS at the settings you believe look nice, then you can add some AA (2x or 4x). If you're getting <= 30 FPS, don't use AA.

 

What's the gfx card in the new laptop?

 

The one I'm currently looking at has Dual NVIDIA GeForce Go 9800M-GTX 1GB DDR3 Video in SLI Mode.

I'm not sure how great of a set-up it is, but I'm pretty sure it can out-do my current 8600M GT 512Mb.

 

Laptops GPUs don't handle AA/AF (More so AA) or heavy particle effects nearly as well as desktop cards, despite having made significant advances in other areas over the years.

 

Hmmm, I didn't know that but I guess it's kinda obvious. I was thinking of ordering a new gaming desktop, but having a laptop would be much easier for me in the coming months.

 

>.> of course weak laptops don't match desktop performance. Laptops that match desktop performance handle these settings just fine though.

 

Meberus, that 9800m GTX SLI setup you're looking at is currently top-of-the line. The 8600m you have right now is really not powerful enough for AA in most games, I've tried (Source games excluded - Yay Valve!). Especially not Crysis.

 

I'm just thankful for my 15.4" 1680*1050 screen! I don't need to use AA cause of the high res and the smaller screen! I would just suggest leaving AA off as your video card is not that great. I would way rather smooth game play than no jaggies!

 

Yeah, I guess trying that stuff on Crysis was just a bad idea in general; though I was curious to see how nice it looked. But when I figured out that it forces Shaders to "High", I stopped.

And I can't wait to get my hands on my new setup.