MAMEWorld Forums - EmuChat - Mame slow compiling

Hi, I was compiling Mame a few weeks ago when I noticed Mame had become slow to compile in MinGW for some reason (takes over 1h 40min). I scanned and scanned for malware but found nothing. So presuming I had some sort of undetected malware I have now done a fresh format & install of Windows 7 64, however the slow compiling remains. I'm using the tools off Mamedev.org & Git, TortoiseGit to update my source from https://github.com/mamedev/mame.git & am using a .bat file executed in the root of the source, with these settings:

set path=D:\Emulation\MinGW\mingw64-w64\bin;D:\Emulation\MinGW\mingw64-w64\opt\bin;D:\Emulation\MinGW\mingw64-w64\Qt\bin;
make -j8 OS=Windows_NT ARCHOPTS=-march=native NOWERROR=1 TARGETOS=win32 TARGET=mame OSD=windows PTR64=1

My computer specs are:

Windows 7 Home Premium 64-bit SP1
CPU: Intel Core i7 2670QM @ 2.20GHz (Up to 3.10GHz) Sandy Bridge 32nm Technology
RAM: 8.00GB Dual-Channel DDR3 @ 665MHz (9-9-9-24)
GRAPHICS: 2047MB NVIDIA GeForce GT 540M
STORAGE: 698GB Seagate ST9750423AS 5400RPM SATA-II

I'm running Avast Antivirus, Comodo Firewall. And have disabled Avast & HIPS in Comodo but with the same result. I've tried other -j* commands and all cores seem to be firing under Performance in Windows Task Manager, but it seems to start off quickly compiling and then gets a bit slower, but overall WAY slower than how quickly it was compiling a month ago. All other programs including Mame seem fine.

Anyone have any ideas what might be happening here?.