Which Was Better?

I've had pretty good experiences with the three processors I purchased: the AMD PII X3 720 Black Edition, the AMD PII X4 965 Black Edition, and the Intel i5 750. I also had good experiences with the three graphic cards I purchased: an ATI HD 4650, and two ATI HD 5770's. I liked the three cases and the three power supplies.
I would have no trouble recommending any of these. I have confirmed that you cannot get extreme overclocks from any of them (although perhaps you could with more exotic cooling). And, I've confirmed that you can get modest overclocks even in a tight case if you use a better CPU HSF and replace the stock rear case fan with a higher volume unit like the Scythe. Specifically, the Intel i5 750 doesn't seem to throw anymore heat than the X4 965 and both run cool with upgraded HSF's. Using a case with good ventilation (like my two Cooler Master cases with 200 mm fans) you can get a bit higher. However, in all fairness, you can get more heat dumped off a high end graphics card than you can off either of these processors. This is why I chose HD 5770's with external exhaust.

I installed my 785 motherboard in the small Gigabyte case along with my OCZ Gold memory, HD 4650 graphic card, and PII X3 720 processor. Since this case only had one small rear fan I swapped with a heftier Scythe fan. The only difficulty I had with assembly was that the motherboard connector wasn't long enough to reach from the power supply on the case bottom all the way across to the connector at the top of the motherboard. So, I had to get an extension. I also had to get a Molex to SATA adapter for one of the drive power plugs since I ran out of newer SATA connectors (like the drives needed) and only had the older Molex connectors left. My mother had an older 2.0 Ghz dual core system that was a bit clunky. It was slow and the graphics were worse than the embedded graphics on the 785 board. With the faster tricore processor, much greater memory, and considerably more powerful 4650 graphics, my mother is pretty happy with the upgrade.

My two big systems are practically twins, they both have quad processors, 8 GB's of memory, HD 5770 graphics, similar drives, and 200mm cooling fans. The only real difference is that one uses an Intel processor while the other uses AMD. I like both systems. In fact, I'm typing this on my Intel box at the moment.

The i5 750 will run FP faster if the code is tight. This would make a difference in a render farm where even a small difference would effect profitability. However, that doesn't really matter since any commercial use would favor whatever system ran their particular software fastest regardless of anything else. Under some circumstances you can get either AMD or Intel quad to run faster; in actual use I doubt anyone would notice any difference between the two. Since I paid the same amount for each, that is good to know.

I do like the Intel CPU retention better than AMD's. The Intel processor is firmly held in place by itself and this can help keep someone from damaging the unit. With AMD, you have to make certain that you wiggle the heatsink to loosen it BEFORE attempting to remove it. Otherwise the suction of the thermal paste along with the looser pin clamps can cause the processor to pull out of the socket while it is still clamped. This is not a good idea since it can ruin both the processor and motherboard. A novice is less like to damage the Intel CPU. On the other hand, the heatsink retention on Intel boards is noticeably worse than on AMD boards. A novice could also damage an Intel board while trying to install the heatsink. However, if you make sure you understand about inserting the feet all the way through the board and only then pushing the spreader pins in place you'll be okay. Even with the less secure heatsink retention I find Intel boards completely adequate for a heatsink of the size I used (530 grams). To be honest, I wouldn't want to go higher than this with an AMD board either size 500 grams is supposed to be the rated limit. Also, it is hard to beat the price tag of $40 coolers.

Overclocking the AMD Black Edition is a little easier because you can adjust the multiplier. On the other hand, the Intel is easier because of thermal throttling. To be honest though, you can overclock either one fairly easily; I spent many hours at this so I think I have a pretty good idea what is involved. In my experience you are more likely to run into quirks of the particular motherboard you are using. I found for example, that the X3 720 required different overclocking on the 785 board than the X4 965 did even though these two processors should be quite similar. Also, the X4 965 required different technique on the 785 board than it did on the 79X board (even though both were Asus motherboards with ATI chipsets). I can't say this for certain about the i5 since I only had one Intel motherboard but I wouldn't be surprised if  it were the case as well.

I also find it interesting to look at what is available now. I can say with confidence that there is nothing out yet that would make me feel that my systems were outdated. I'll probably look over the new stuff and comment in another article. In particular I've been curious about Intel's on-chip Sandybridge graphics as well as how nVidia is stacking up with AMD's ATI offerings. I wasn't that enthusiastic about AMD's hex core processors but I seem recall that AMD's bulldozer processors will be out soon and they might be worth a look.