From my testing, FTM 2014 (64-bit) runs about 50% faster than FTM 2014 (32-bit) on the same file and the same computer.
I use a 27" iMac 64-bit with Windows 7 Pro (64-bit) running under Parallels 7 with 16 GB of RAM on each side so I can run very interesting comparisons.
The early betas of FTM 2014 were 32-bit, so I was able to run the comparisons on the same test file and same computer and record the results on a genealogy report, a 3x3 EFT and large kinship report.
FTM 2014 32-bit is no faster than FTM 2012 32-bit
In my case, I am using 16 GB of RAM, 3.2GHz i5 processor and a conventional hard drive. It is faster again with a solid state drive.
File size around 7,500 people
Note that running 64-bit and less than 4GB of RAM won't show any real improvement.
32-bit can only address 4GB of RAM and typically in Win XP, Win 7 etc, 32-bit; about 1GB of RAM is needed to run Windows and other functions, so on your set-up you only have about 2.5GB of RAM to run FTM. I think this is far too low for a 'large file'.
64-bit can comfortably use 100GB of RAM or more.
Makes a big difference to databases like FTM
Also FTM (Win) is very Windows dependent, ie it uses a lot of Windows functions via .NET. If your Windows is a bit 'suss' things will be even slower.
FTM Mac3 (in beta) 64-bit really flies compared with the Windows 2014 64-bit equivalent as it doesn't have to deal with .NET.
About 50% or more faster again than 2014 64-bit and I can get it to load in 2/3 seconds.
So maybe consider upgrading to a 64-bit Win 8.1 computer with at least 8GB of RAM and a fast processor like an i7 and also a SSD or combo SSD and conventional drive.
Or maybe just buy a good iMac? :-)