maxinc Wrote:Never use PCI SATA controllers. PCI has limited bus speed and will make your system dead slow once you connect enough drives. Get something with at least one PCI-E 4x slot which can accommodate an additional 8 SATA ports. PCI-E 1x controllers would only give you 2 extra ports.
For 4TB NAS it's pretty much irrelevant, we're not talking about a lot of hdd's here.
I have an ATOM based NAS (D510) running 2 SATA hard drives running off the motherboard and 4 running off a PCI expansion board, totalling 10TB and it runs more than adequately to serve 2xXBMC boxes, 1 WDTV Live and 3 PC's. Having load tested it, I've been able to play HD content on all media players simultaneously, and have sabnzbd downloading at my full speed of around 9MB/sec with ease.
The bottleneck is the network more often than not before read/write speed issues come into play in most home NAS setups. SATA 3 runs at 3Gbit/sec, SATA 2 runs at 1.5Gbit/sec, both significantly outperform a 1Gbit/sec network when you add network overheads and congestion (which would be required to max out the controller cards).
Unless you do some serious heavy lifting with multiple devices simultaneously, the key factor in building a cheap home NAS is the CPU and RAM.