Using space over 2tb mbr boot

I have a dell t7400 which looks to not support gtp via bios (latest firmware). I have a lsi 9620 8i with 4 sas 2tb drives installed running raid 10. The virtual drive shows as 3.8tb, in windows 7 pro 64bit only get 2tb showing usable. Paragon HD Manager 12 shows the unallocated space but cannot do anything with it. Tried using gtp but system would not boot and had to switch back to mbr with paragon boot media.
Like the speed and redundancy of raid 10 if I could just use the extra space would be...

Using space over 2tb mbr boot