"Zoneminder" is a pretty CPU-hungry and annoying to setup and manage (exactly what you would expect from such software for such price). Exacq
makes much better software - better performance (in terms of video encoding), more user-friendly and easier to setup, it also runs on Loonix (if you're into that) and has mobile apps even for Windows Phone 8. They have a 45-day 4-camera trial version available, try them.
Overall in my searching so far I could not find a decent NVR with any sort of good reputation and capable of 720P video for under $200. Maybe someone has a recommendation for any good ones I'm not aware of?
Under $200? Probably not, but for exactly $200 you can get, for example, Synology DS213j. It does not have HDDs but you have to buy them anyway, even if you waste around $200 (this includes RAM price) for an Atom-based PC barebones (and you should use at least 2 HDDs in RAID1 if you don't want to lose recorded data right when you need it due to one HDD going bad). According to Synology, this NAS is capable of "125 FPS @ VGA (640x480), 50 FPS @ 720p (1280x800),
25 FPS @ 1080p (1920×1080)" when recording videos from cameras, meaning that, for example, you can use 2 720p cameras, each outputting at max of 25fps, or even 2 1080p cameras with about 12.5fps for each, or any similar config. If you need a slightly more capable device, there's a DS114 model, which has more power available but only a single HDD bay (so no RAID). Synology includes 1 free camera license with each NAS, the extra licenses cost money (and cost can be significant) but since you only have 2 cameras - it would cost you around $50 for extra camera license for second camera. You might even find these devices used, for slightly less price. If you need to compare their features (including the camera compatibility and the IP camera video encoding capability), use this: http://www.synology.com/en-us/products/compare_products
Anyway, like I said before, whatever you'll buy - make sure it will be compatible with whatever IP cameras you have.
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