what mac to buy for several hour rendering per day?

For the kind of loading you are talking about, either the 4 or 6 core Mac Pro would be best. The iMac is a very powerful machine, but the very thin size means work to remove the heat generated by heavy duty rendering.

The CPUs used are very different...the Intel i-core processors are consumer grade units. The Xeon is a server-grade professional processor. If you look at the heat dissipation for both, the i-core in the iMac has a Thermal Design Power of 84 watts. The Xeon has a TDP of 130 watts. That means the Xeon can run at a heavier load for a longer period of time before speed run-back is forced on it.

To run hours long rendering you will b e loading the processore pretty heavily. For a long life machine, the Mac Pro would be the better option.

And one more point, not advertised, the Mac Pro Xeon is a socketed processor, i.e., it is replaceable. The iMac processor is soldered to the logic board.

a.j.ishtay wrote:

can it handle like 50 hr of rendering per month for 3 years for example?

Really, that should be no problem.

There are plenty of hardware-savvy folks here who will give you good advice about what to buy. But your comment about client demand for FCPX is also very interesting. If you could elaborate a bit more that would be great.

Russ

To see more on the processor/system power and thermal loads, see:

Mac Pro: http://support.apple.com/kb/HT2836

iMac: http://support.apple.com/kb/HT3559

Some really good replies here!

To help the original poster, what you're trying to do is really commercial work as opposed to hobbiest usage. For commercial use it would be much to your advantage to go with a more robust machine that can handle the heat better and that is the Mac Pro. The cabinet is much larger, there is more room inside for heat dissipation, fans for the logic board and fans for the graphics card(s), heat sinks, etc.

Weigh the incremental cost of the Mac Pro against the cost of what would happen if you were in the middle of a project, spent hours working on it, and the system failed causing the data to be lost. Most likely there would be a lot of other video files that hadn't been archived yet and who knows what would happen to them.

That doesn't mean to say that nothing would ever happen to the Mac Pro but the odds are it would be less. Another fringe benefit of going with a Mac Pro is it has more upgrade and "future-proof" capability.

Speaking of robustness. A Time Capsule could be a useful addition and, for your use, and better yet, a RAID system (Mac friendly for minimum maintenance) is almost a requirement down the road. And with your anticipated usage, that would be a short road!

Another comment I'd like to add in is that FCPX likes lots of memory on the graphics card. 1GB is workable but 3GB would be super and the rendering time would be reduced immensely.