I am debating between a consumer PC and workstation, I might have to end up with the workstation due to buying through small business but the consumer seems to be a better performer. The 2 processors are the core i7 975 3.33Ghz and Xeon W3540 2.93Ghz about how much of a difference is there between the 2, the main use will be heavy Photoshop editing as well as running multiple design programs simultaneously with large files. (12GB of RAM for either system to help with this.)
The 7 box is actually cheaper, it uses a different video card (twice the video memory, but it is a consumer grade card) and non-ECC memory.
My main issue right now which is why I posted in here and the video card thread is to figure out if fighting for the consumer based box (and a few hundred extra for other things in the budget) is worth it for the bump in performance or go through normal channels with the workstation.
The bean counters will like the lower price of the i7.
The beaurocrats will insist that you buy the way it has always been done.
If either is important to you, don't fight it.
There will not be a major difference with either computer.
ECC ram is more expensive but all ram is quite reliable. Not a real issue, I think.
Workstation motherboards may have more than 6 ram slots and may be able to handle lots more 2gb sticks of ram. CS4 may be able to take advantage of 24gb or more.
Getting 24gb using 4gb sticks gets expensive.
The different video cards may well be a big issue with CS4. Check that part out carefully.
The clock rate differences would favor the i7, but not by enough to make a big issue out of it.
Is the 6 core 32 nm gulftown a possibility in your timeframe?
Ill say that depending on the features you need, both processors will work just fine, if you are worried about price of your GPX card on the xeon, i would go i7 but i would reccomend cheaper still.
take a look at the i7 960 minor differences from the i7 975 extreme for half the price for example -130mhz clock speed and a 4.8gt/s difference also the BUS/CLK ratio is 24 instead of 25. these differences are not even going to be noticeable, especially if you overclock it.
and as far as your xeon the only technology that the other two do not have is demand based switching, whether or not thats important to you will be your decision.