The "TESV Acceleration Layer" is a new mod that claims to increase Skyrim's frame rate by a clear 30-40 per cent, without affecting graphics quality... or anything else for that matter. It does this by using rewritten SSE2 instructions and removing redundant code from the game. This isn't even the best (or worst) part — according to the mod's author, the boost could be in the area of 100 per cent, if Bethesda had bothered to optimise its code.
It's a tall accusation for a random guy on the internet to level at one of the biggest gaming studios around, but then, we have stuff like Hot Coffee, so I'm willing to give him the benefit of the doubt. That, and he sounds like he knows what he's talking about. But first, the mod.
The mod itself is actually a DLL that requires the Skyrim Script Extender to operate. The author, Arisu, says the library increases performance by up to 40 per cent in "all CPU-dependent situations", with cities being the prime example. It does this by cleaning up some messy routines that do things they don't need to and optimising simple functions that are called many times during each frame of gameplay.
The description also mentions that Bethesda built the game without a number of special flags that optimise code paths. Oops.
OK, so that's out of the way. What about the 100 per cent thing? Arisu's explanation is somewhat in-depth, but essentially, if Bethesda was willing to do the proper optimisations, the game would be going much, much faster. It's hard to verify how accurate this information is, so we'll need to get in touch with Bethesda and see if it can expand on the subject. The core issues with the game are its lacklustre use of multi-threading (which Arisu admits is not a simple thing to address), loads of redundant code, lack of optimisation flags at compile time and generally unoptimised instructions on critical code paths.
I have yet to crack open Skyrim, so, anyone out there who's brave enough to give it a go, please do, and let us know the results. If they're positive, then this news could have far-reaching consequences for Bethesda (and its programmers).
Image: Duncan Harris