Mass Effect is a popular franchise of sci-fi roleplaying games. The first game was initially released by BioWare in late 2007 on Xbox 360 exclusively as a part of a publishing deal with Microsoft. A few months later in mid-2008, the game received PC port developed by Demiurge Studios. It was a decent port with no obvious flaws, that is until 2011 when AMD released their new Bulldozer-based CPUs. When playing the game on PCs with modern AMD processors, two areas in the game (Noveria and Ilos) show severe graphical artifacts.[…]
What makes this issue particularly interesting? Vendor-specific bugs are nothing new, and games have had them for decades. However, to my best knowledge, this is the only case where a graphical issue is caused by a processor and not by a graphics card. In the majority of cases, issues happen with a specific vendor of GPU and they don’t care about the CPU, while in this case, it’s the exact opposite. This makes the issue very unique and worth looking into.
An extremely detailed look into the analysis and fix for this very specific bug – and a download with the fix, of course.
Well, it’s an interesting article and props to them for getting it working. I wish they dug a little further to identify the exact difference between D3DXMatrixInverse and XMMatrixInverse on AMD CPUs. They speculate that it could be a precision issue, but even rounding differences doesn’t clearly explain why the rendering goes black… Their job is done and they wrote a patch to avoid the faulty branch, but it seems like they got too tired of debugging to solve the mystery of the faulty branch, haha.