I would.. but one problem, well two of them actually. Since the 2009 single-quads are capable of using all the bloomfield core i7 and xeon(w3520,w3540,w3565,w3570, and w3580), Apple did not leave room inside for the microcode needed to run the core i7-980x or its xeon brother.
This would require B1 stepping which I have D0 stepping.. Another factor is the situation that in order for the 980x to work in the single-quad core, the microcode would have to be flashed to the EFI chip inside the mac pro for it to be used and even if this can be done, there are no guarentees that the machine would even be bootable anymore, or it may boot but nothing would come up... Idk, has someone ever gotten ahold of the microcode to do this?
I didn't want to go PC, as building a hackintosh is complicated at this point.. Sure, I'd like to buy any PC and put mac os x on it, as I do own it(bought for 29.99), but not all PC's will support it.
For the price, why don't you go for the new Hex-core although none of them supports ECC memory. If you were going to use 1333 memory, You could go for cheaper non-ECC ones anyway.
Orig conf: w3520 2.66 quad-core single
6GB of ddr3 1066 memory
4 x1TB hard drives - total 4TB.
Two superdrives 22x
GPU: Radeon 4870 HP.. I know the GT120 is crap, therefore got rid of it.
But the other problem is even with my new processor and non-ecc memory, Apple still has 1066 locked in so going to 1333 isn't going to happen, at least on the mac pro.
Um.. Well, not exactly sure how 'PC terms' differ from standard math.
1333 / 1066 * 100% = 125%
So 1333 is 125% the speed of 1066.
The faster memory will be of relevance in memory-intensive applications. Large programs which wish to store large parts of themselves in your memory will benefit from faster memory.
But you'd be crazy to leave a PC with those specs at stock. Once you start upping the reference clock, you'll have to start lowering the multiplier for the RAM to make sure it doesn't melt. You could easily have 1333MHz memory at 1800MHz without breaking a sweat.
Wise choice on the i7 over the Xeon. The W3580 is seriously overpriced for the 'Q3 2009' punch it packs. An i7 isn't going to be anywhere near the bottleneck for your system. That hardware's overkill at that point.
Your bottleneck will probably be your HDD at this point. (vs an SSD)
Unless your GPU is brought into the equation, which is a severe weak point of most Macs. (GT 120's are rebranded 9500GT's)
And add to the fact that the i7-980x or its xeon brother won't even work in ANY 2009 quad-core single mac pro, as it uses B1 stepping plus one would need to flash the microcode needed for the processor to work.. Apple has this and I doubt even if a 2010 were to come out someone couldn't successfully on here copy over the microcode and develop a FLASH BIOS or EFI flasher to flash over the new microcode.. Impossible? Maybe.. I would pay someone for it, though not really worth it unless someone on here knows that it will work for sure when flashed.
i9's are incredibly silly when
you can't even order a Mac Pro from Apple with an SSD.
i9's are incredibly silly when
you can't order a nVidia Card past the 9XXX line in a Mac Pro from Apple.
i9's are incredibly silly when
you can't order a 5XXX ATi GPU in a Mac Pro from Apple.
i9's are incredibly silly when
the Mac Pro uses 1066MHz RAM. (DDR
2 was available in that speed, that's not even real DDR3..)
Does no one understand what a bottleneck is? 
You buy (a) $1(+)k Processor(s) and use almost none of it. Why would you do that?
Ok, is there a way for me to use 1333 on my mac pro now that I have a i7-975 in my system? I thought Apple's firmware locked all of us even duals at 1066 ddr3.. is there a way to go beyond 1066 into 1333? The core i7 975 I have supports 1066 and 1333 as well as the w3580, but it seems Apple has us locked in at 1066 and can't go beyond that..
As for SSD drives? They are out of my price range!! How many years will it be for someone to walk into a Best Buy and buy at least a 1TB SSD drive? I have 4x1TB drives in my system right now.
Has no relevance at all, you can use SSDs in your Mac Pro as many do. None of the big certified workstation vendors offer SSDs on them. Even if Apple did you'd pay a lot for some brand they chose, unlikely you'd get even one of the best 3 choices around.
If you are a gamer maybe. Many users don't need a powerful graphics card at all.
Not even real DDR3? Only the top tier processors even support more than 1066MHz without overclocking. On a dual socket board with the second rank of DIMMs installed it won't run at more than 1066MHz unless you have a board that allows it to be reconfigured, and I only know of ASUS and Tyan ones that do.
You can can max out six 3.33GHz cores with 800MHz memory, a 5400RPM drive and integrated graphics. It just depends on what you are doing. Even if you can't utilize all 6 cores, you are still getting that 3.33GHz clock speed. Also there is no i9.
Sorry to break your post down like that, but you posted a lot of ill-thought out statements.
Given I don't use pro apps at all, name me some consumer apps that I would have trouble with using non-ecc memory?
Core i7-975 and Core i7 980X are similarly priced, they are both near $1K. It really depends on how you use multi-cores. For gaming, it's a non-issue. For parallel computing, more cores mean faster speed if the code is optimized properly. Indeed I don't find SSD is very useful since the code doesn't read/write disk often. The fastest SSD won't help 1% of my application.
Core i7 doesn't support ECC. Some CPU/Memory intensive applications could run for weeks even months. Without ECC support, such applications usually crash (largely due to memory error) in several days.
