There's a little thing called DirectX 10.1 API and it's causing quite a bit of a storm in the gaming world. Or, more accurately, in that part of the gaming world that plays Assassin's Creed and likes conspiracy theories.

Let's start from the top. The above-mentioned API was supposed to fix one of the most obvious issues with DirectX 10, that of slow anti-aliasing. Assassin's Creed for the PC is one the few games that supports the 10.1 API. Some gamers remarked that the new implementation of anti-aliasing made the game run faster on top ATI videocards, like the ATI Radeon HD 3000 implementations. Considering the fact that Assassin's Creed is one of those titles that bears an Nvidia logo, called "The Way It's Meant To Be Played", that is telling gamers that the game is best played with a graphics card from Nvidia, it's clear that there were people who found themselves a bit annoyed with the increased ATI performance.

Then Ubisoft released a patch that was designed to eliminate the support for the 10.1 API from the game. They said that "the patch will remove support for DX10.1, since we need to rework its implementation. The performance gains seen by players who are currently playing Assassin's Creed with a DX10.1 graphics card are in large part due to the fact that our implementation removes a render pass during post-effect which is costly".

Apparently, the whole purpose of the new 10.1 API is to remove that pass, a pass that 10.0 added without there being any need for it. So it seems that the Ubisoft explanation does not pass (pun intended) close inspection. And this is where the conspiracy begins.

The best-liked theory is that Nvidia may have launched veiled threats at Ubisoft regarding a certain amount of money that was supposed to go in a co-advertising deal. Representatives from both Nvidia and Ubisoft have denied such claims. But there are enough facts on the ground to support the claim that something along these lines has happened.

Meanwhile, the best thing regarding the new patch for Assassin's Creed is not to install it if you have ATI hardware capable of DirectX 10.1 rendering. Otherwise, get it and patch the game.