What are the differences between GTX 650 and the GTX 650Ti

The core CraftBukkit server (Bukkit's implementation) itself is equivalent from my experience.

But since anyone that can copy/paste Java can create a plugin, it really depends on which plugins you use. It pays to do your research here and understand the impact of each plugin you decide to install.

You can sort of rely on the most popular plugins (plugins with threads that have a lot of comments compared to others) to be fairly reliable. If you start delving into lesser used plugins, spend the time to read the entire thread and understand exacly what the developer is trying to accomplish. If you have any coding experience at all, look through the source code to get an idea of what it exactly does.

What I would say in summary is that a significant portion of most servers (small, medium, and large) run CraftBukkit successfully. There are problems for sure, but there are problems with Vanilla also. Nothing's perfect.

This is a great question because other than "is AA on or off?" I hadn't considered the performance implications of all the various anti-aliasing modes.

There's a good basic description of the three "main" AA modes at So Many AA Techniques, So Little Time, but pretty much all AA these days is MSAA or some tweaky optimized version of it:

1. Super-Sampled Anti-Aliasing (SSAA). The oldest trick in the book - I list it as universal because you can use it pretty much anywhere: forward or deferred rendering, it also anti-aliases alpha cutouts, and it gives you better texture sampling at high anisotropy too. Basically, you render the image at a higher resolution and down-sample with a filter when done. Sharp edges become anti-aliased as they are down-sized. Of course, there's a reason why people don't use SSAA: it costs a fortune. Whatever your fill rate bill, it's 4x for even minimal SSAA.

2. Multi-Sampled Anti-Aliasing (MSAA). This is what you typically have in hardware on a modern graphics card. The graphics card renders to a surface that is larger than the final image, but in shading each "cluster" of samples (that will end up in a single pixel on the final screen) the pixel shader is run only once. We save a ton of fill rate, but we still burn memory bandwidth. This technique does not anti-alias any effects coming out of the shader, because the shader runs at 1x, so alpha cutouts are jagged. This is the most common way to run a forward-rendering game. MSAA does not work for a deferred renderer because lighting decisions are made after the MSAA is "resolved" (down-sized) to its final image size.

3. Coverage Sample Anti-Aliasing (CSAA). A further optimization on MSAA from NVidia [ed: ATI has an equivalent]. Besides running the shader at 1x and the framebuffer at 4x, the GPU's rasterizer is run at 16x. So while the depth buffer produces better anti-aliasing, the intermediate shades of blending produced are even better.

This Anandtech article has a good comparison of AA modes in relatively recent video cards that show the performance cost of each mode for ATI and NVIDIA (this is at 1920x1200):

                       ---MSAA---   --AMSAA---    ---SSAA---
                 none  2x  4x  8x   2x  4x  8x    2x  4x  8x
                 ----  ----------   ----------    ----------
ATI 5870           53  45  43  34   44  41  37    38  28  16
NVIDIA GTX 280     35  30  27  22   29  28  25

So basically, you can expect a performance loss of..

• no AA → 2x AA

  ~15% slower

• no AA → 4x AA

  ~25% slower

There is indeed a visible quality difference between zero, 2x, 4x and 8x antialiasing. And the tweaked MSAA variants, aka "adaptive" or "coverage sample" offer better quality at more or less the same performance level. Additional samples per pixel = higher quality anti-aliasing.

Comparing the different modes on each card, where "mode" is number of samples used to generate each pixel.

Mode   NVIDIA   AMD
--------------------
2+0    2x       2x
2+2    N/A      2xEQ
4+0    4x       4x
4+4    8x       4xEQ
4+12   16x      N/A
8+0    8xQ      8x
8+8    16xQ     8xEQ
8+24   32x      N/A

In my opinion, beyond 8x AA, you'd have to have the eyes of an eagle on crack to see the difference. There is definitely some advantage to having "cheap" 2x and 4x AA modes that can reasonably approximate 8x without the performance hit, though. That's the sweet spot for performance and a visual quality increase you'd notice.