I'd built an OTA DVR for my parents using a mATX (gigabyte) board running a 945 chipset variant (945L, maybe?). The board had several PCI-e x1 slots, which we initially populated with two Hauppauge 1850s; those were recently switched up to 2250s (resulting in 4 tuners total, which then became a requirement for all future DVRs).
However, throughout the 18-24 months that this system ran, several minor issues came up. First, the system started w/ 2 drives in RAID 1, and it was constantly rebuilding the array. So, I converted it to a RAID 0 and dropped a PATA laptop drive in to handle the OS (TV shows went onto the now-RAID0 array). That worked well for about 6-8 months, when suddenly the IGP started throwing errors in Windows, resizing the screen when coming back from standby, and so on. After troubleshooting, I decided to work-around instead; we added an Nvidia 9400 GPU and the problems went away again. But - finally - the system stopped booting altogether (felt like a chipset failure).
So, I set out to build a new DVR with a list of simple requirements set by my mother. The computer must be:
- the same size or smaller
- able to record 4 shows at the same time
I settled on the Zotac NM10-DTX after testing an Hauppauge 1950 on my Zotac mITX ION board and finding its performance excellent (even for a USB implementation). My hope was that the mDTX board's two PCI-e slots would hold the two 2250s, and that I'd be able to keep the fanless board cool using the single 120mm fan in the Silverstone SG-05 (B - for beautiful).
If it worked, that would fulfill all of my requirements!
The board fit perfectly in the SG-05B, and the two TV tuner cards only got a little in the way when hooking up the front audio to the HDA header towards the back of the board. Cable routing was very easy, allowing for plenty of good airflow to the fanless HS (CPU stays around 60C - which isn't bad).
Upon initial installation of Windows 7 Home Premium, I needed to install drivers for the Hauppauge cards as well as the JMicron RAID controller (which I'm not using but cannot disable in BIOS). Additionally, I needed to install the Intel chipset drivers PLUS swap out the default-MS AHCI driver for the Intel one, or else the secondary HDD would not detect on wake (thus making it impossible to record shows at all).
One unknown prior to the build was whether or not the board's HDMI output would include an audio stream; there's lots of information about Pine Trail/ION combos having it, but I wasn't able to find anything about how NM10 alone would handle it. Luckily, it did just fine, passing audio & video to the receiver w/o a hitch.
The second unknown was whether my parents' TV would accept/like the fixed resolutions which the BIOS-configurable HDMI port uses (1280x720 by default). This result was a little weirder - Windows identified the TV as a 1280x1024 monitor, which seemed to cause a bit of overscan when running @ the default output. When I tried bumping the BIOS-controlled output resolution to 1366x768, the TV didn't display anything (forcing a CMOS reset...). Again, luckily, configuring Windows Media Center worked around the problem, even if I could only see about half of the start button's circle and only the time (date was cut off) while on the desktop & with the default BIOS video config re-set.
The final unknown was whether or not the dual-core, HT Atom (D510) would be able to record 4 HD streams at once. Obviously the 2250s do a lot of the necessary work on the cards themselves, but there was still some doubt in my mind that the Atom CPU would be able to handle recording and playback at the same time. I shouldn't have worried, as it did just fine, barely breaking a sweat as it worked.
I just got back from installation and configuration, and my parents are very happy with the build.
For anyone looking to assemble their own tiny OTA DVR which can record up to 4 HD streams simultaneously, I can confirm that the Zotac NM10-DTX paired with Hauppauge 2250s in an SG-05B case works.
In fact, once my aging SD11G5-based DVR breaks down I will probably replace it with a similar - if not exactly the same - build!