Ditto thanks to Jonathan_S
What I think makes the most sense is to use JMFS to upgrade your stock 340 GB Premier drive to the maximum 2 TB (wheee) and then store your original drive clearly marked as to what it is and why you're keeping it
so that when you stumble over it a few years from now you won't be tempted to reformat it or toss it or give it away. In fact I would go so far as to re-box it in the packaging that the new 2 TB drive came in (unless you bought a bare metal drive that's only wrapped in anti-stat bubble-wrap.
Others have their own opinions about disk drives, some are informed opinions, but others are uninformed or maybe just misinformed
about why you should put the best quality
drives in versus the cheapest. Cheap drives are cheap for one reason; the cheapies are generally production culls that work fine in less demanding environments but maybe didn't fully meet spec. for CDCS (Continuous Duty Commercial Service) or maybe they're off brand clones. I've had commercial PBX (Mitel) and Voice Mail (Octel) systems running for 15+ years (130,000 + hours) on the original drives (on clean power in a temp-stable, dust-free environment) so I don't buy-into this theory about "a drive is a drive". 15 years ago those commercial-grade 40-meg and 2.0gb (respectively) drives fetched prices upwards of $600 but they also ran for 15 years and are still going. Even if shut off, they'll still spin right up.
With today's prices for top quality drives not even double the cost of a cheapie, why would you ever risk your data (recordings) on some P.O.S. drive? To me, just the amount of time (labor) involved in HDD replacement along with the frustration of HDD failure way more than offsets the cost differential.
In most computer applications I use and swear by WD Caviar "Black" drives. They run at 7200 rpm with a 32 MB cache. The "Blacks" are also considered "server grade" and come with a 5 yr warranty vs a 3-yr warranty on the WD green model.
On the other hand, the WD "Green Power" drives use only half the power and thus run substantially cooler.
I also realize that you don't need the performance (speed) for what basically amounts to a "storage" drive on your DVR. I just hate having the dang thing fail.