So I've been playing around a bit with optimization settings in my compiler. For some reason I thought some x64 CPUs didn't have SSE2, but apparently they all do.
What is SSE2?
SSE2, Streaming SIMD Extensions 2, is one of the Intel SIMD (Single Instruction, Multiple Data) processor supplementary instruction sets first introduced by Intel with the initial version of the Pentium 4 in 2001
So it's been a part of the CPU industry for 9 years now, and since RetroCopy requires modern CPUs anyhow I thought this should benefit many users. In the 64bit builds this has been enabled anyhow as all 64bit CPUs support it, it only affects the 32bit builds.
One thing that surprised me is now the 32bit build is faster than 64bit build with SSE2 optimizations enabled, only slightly though. This is in running the benchmark, which is the Sega Master System core. This speed difference may not apply to all emulator cores, I have a feeling the Megadrive core would be faster in 64bit mode.
This also isn't taking into account your video/sound drivers which likely run faster in 64bit mode, this is just pure emulation related speed. So I still recommend to run the 64bit version for the better experience. So if you don't have a SSE2 capable CPU RetroCopy v0.700 is the last one you will be able to run. For those that do, expect a speed boost!
Here is a list of CPUs which support SSE2, see if yours does :-
* AMD K8-based CPUs (Athlon 64, Sempron 64, Turion 64, etc)
* AMD Phenom CPUs
* Intel NetBurst-based CPUs (Pentium 4, Xeon, Celeron, Celeron D, etc)
* Intel Pentium M and Celeron M
* Intel Core-based CPUs (Core Duo, Core Solo, etc)
* Intel Core 2-based CPUs (Core 2 Duo, Core 2 Quad, etc)
* Intel Core i7
* Intel Atom
* Transmeta Efficeon
* VIA C7
* VIA Nano