I don't know which compiler the builders are currently using but I have noticed other programmers that use Intel's compiler.. It can optimize code for Intel Processors.. From what I have seen it does a very good job.
http://www.intel.com/software/products/compilers/
What one programmer said about the intel compiler (for the shareaza program):
"That said, the Intel compiler sure optimizes like crazy. The Intel builds use a lot less CPU to do the
same job. Another way of saying that, those builds are a lot faster."
So if it can work that well for a p2p program it should work just as good for a video player.
This is what Intel says about their compilers:
"Maximize your application performance on Intel® architecture
Intel® Compilers help software run at top speeds. Compiler optimizations include support for Streaming SIMD Extensions 2 (SSE2), software pipelining, and support for Intel® XScale® microarchitecture. Intel compilers support multi-threaded code development through auto-parallelism and OpenMP* programming. Inter-procedural optimization (IPO) and profile-guided optimization (PGO) can provide even greater application performance. With Intel compilers, develop high performance software for the following processors:
* IA-32 processors: Intel® Pentium® 4 with Hyper-Threading Technology, Intel® Xeon�, Pentium M, Intel® Celeron®, and Pentium III
* Intel® Itanium® 2 processors
* Intel® Personal Internet Client Architecture (Intel® PCA) processors"