linksys wrt3200acm seagate

I got a brand new WRT3200ACM router. It works great, but when I connect a Seagate 8TB drive to it, the computers only recognize it as a 4TB drive. To summarize: 1. The router is a WRT3200ACM. 2. The drive is a Seagate STEL8000100 8TB drive 3. The drive is formatted with NTFS. 4. When I...