At the risk of committing heresy, I might suggest that the situations in which a Mac Pro is the only viable solution vs. an iMac are becoming more fringe all the time.
This is how I see it as well.
Generally speaking, the enterprise market is getting more complex as well, due to Intel releasing Xeons on 3 sockets once they've gotten all of the Sandy Bridge parts out (LGA1155 for entry level, LGA1356 for mid-level, and LGA2011 for the high-end segment of the market). The bottom end may seem a bit weird at first glance, but it would matter for those with less stringent performance needs, but still require ECC memory (i.e. software is recursive and errors cannot be tolerated).
Yeah... I added that into the initial analysis... And the iMac was still over a cool grand cheaper.
Let me put it another way... If you think a top of the line iMac with a Promise TB RAID is expensive, wait until you see the cost of an equally equipped Mac Pro!!!
I'm actually a little surprised at the cost of the Promise Pegasus units, as I did expect them to be more expensive due to enterprise disks needed for stability reasons.
Keep in mind however, that if you need to use a 3rd party RAID card in a MP (more ports, levels OS X cannot perform, or more performance than the ICH can deliver), then you'll need to plan for enterprise grade disks due to the recovery timings programmed in the disks firmware (consumer disks tend to be unstable on such controllers).
So the cost of the storage system will be even worse.
However, if say 4x disks will work, and only 0/1/10 or JBOD are needed, the MP can handle that without the need of enterprise disks or a controller. Thus the cost would be cheaper under these conditions.
Cheaper solutions may become available for the iMac or laptops via Thunderbolt ports (i.e. software implemented RAID, and the TB chip is attached to a SATA controller + PM chip), but I don't recall seeing an announcement for such a product yet.
Hi
Here's what was reported at Intel's TB launch in February:
The company (Intel) also said there are no plans for a PCIe adapter card for Thunderbolt; the only way to get it will be with a new computer/motherboard.
That may be because of the complexity of integrating the graphics card signal with the PCI-e bus data.
There are ways to actually do it, and have been covered in other threads.
As per an actual PCIe Thunderbolt card, one has already been announced by Matrox (MSRP = $299, and it gives the impression it's DATA only, so no video signal). Not exactly cheap for an interconnect that was claimed to be low cost (TB chip sells for ~$90 USD in quantity, which is almost double what the LightPeak codename was claimed meet @ $50 USD, and was more complicated due to the optical transceivers).
