RAID 5 3TB Hard drives

Hi Guys, I am trying to set up a Raid 5 array on my computer. I have a GIGABYTE GA-890FXA-UD5 motherboard with 5 3tb drives. Using the on board Raid I am getting upwards of 550MB/s Read speeds, but only 30MB/s write speeds....... I tried multiple different setting, but couldn't get it any faster. I went and bought a HighPoint RocketRAID 2720SGL, but unfortunately it is not compatible with my motherboard..... I did manage to get it up in windows one time with some fiddling and did a benchmark, speeds were 600+MB/s read and write, but after a reboot the card completely lost the array and failed to boot to windows. I am looking either for a way to boost my current mobo, get a new mobo that would be faster or get a compatible raid controller for my mobo. I dont need 600MB/s write speed I would be fine with 100-155MB/s. I want to keep this under $300. Let me know what you guys think, Thanks and have a happy 4th of July.