Couple points to make based on some older posts.
It's $3,500 for a dual quad Mac Pro and it costs $70 to get 16GB of RAM from a third party such as otherworldcomputing. Additionally, your comparing this against a pre-built yes? You're not actually suggesting you can get a PC with the equiv. processing power as the above Mac Pro from a retailer for about $1100?
Mac Pros are not typically deployed in large companies. They are used in smaller places with less infrastructure, if I were to really take a stab at it, I'd say the VAST majority of Mac Pro towers live in studios of 20 or less artists.
At that purchasing scale, it is actually totally reasonable to simply buy custom built PCs from a 3rd party supplier or IT company and have them support it. You're not deploying hundreds of machines where a 1% fail rate compounds to mean you have a daily headache in regards to systems.
Look at it this way with a hypothetical. We have a 20 artist studio doing graphic design work for print, web and that type of crap let's say. Our choices are as follows:
2.8 GHz Nehalem
3GB RAM, you then throw it in the garbage and replace with 3rd party 16GB. I am absolutely conceding on the 3rd party RAM issue considering our 150 artist studio does that...every machine is required to have minimum 24GB and we're turning over to 48GB slowly. That gets prohibitive with Dell, Apple, etc., who happily charge you $1,000 to install $100 RAM.
Total cost = $2,800
PassMark score = 5,000
4.8 GHz Sandy
Total cost = $1,400
PassMark score = 13,000
If we're buying 20 machines, I save $28,000 by NOT using Apple. I also get approximately 360% MORE computing power.
The parts in my custom PC are much higher quality (Apple, Dell, etc, use completely trash motherboards, PSUs, etc). In addition, my custom PC can be upgraded to anything no matter what year it is as long as motherboard mounting standards remain the same and we keep using the same 24pin power connectors, etc. All it needs is a new mobo + proc.
Sit down and REALLY think about how spectacularly your hardware would have to fail on you, crash on you and die on you to cost your business $28,000.
Once you start looking at software licenses, this begins to look even more stacked in PC's favor; due to the difference in computing power, you effectively get 2.6 licenses on PC for every 1 on Apple in terms of amount of CPU work that can be done.
I own 6 custom built PCs now myself for work and haven't had issues with anything at all. In fact the biggest issue I've had was looking at how much I've spent on Dell workstations for myself in the past that I could have saved.
Oh and one last thing, you mentioned Xeon being more of a "workhorse" CPU than a consumer chip. There simply is no such thing. It's all just electrons firing down pathways several billion times per second, the only thing ACTUALLY different on a Xeon is multiple QPI links; a feature that obviously isn't required for single CPU machines. The Xeon E3 lineup for example is quite literally cloned from the Sandy i7 lineup, even the prices are identical.
Some chipsets are more "professionally" oriented than others, but I don't think anyone can seriously tell you that P68 delivers any discernible difference in user experience than X58 for 99% of purposes, including in the professional realm...and again, the Mac Pro deployments aren't handling heavy workloads, they are beautiful paperweights sitting under 10% CPU load all day long.
Perhaps the REAL kicker in all of this, what is Apple's support ACTUALLY like on the Mac Pro? Will they make 24/7 service calls to your door with replacement parts and support staff? Cause if I'm spending $4,000 on an Apple and have to either take it to a Mac store for service or have an IT staff anyway, then I am truly speechless.Edited by kweechy - 11/4/11 at 12:52am