That graph is completely misleading. There is one other major difference between the 3 other than just stock Frequency speeds, such as Multipliers (Unlocked vs Just Increased) and that in turn directly effects the Overclock ability of the Chip which effects the Frequency speed.
Just using my favorite company because of their tech support for demonstration purposes.
EVGA has motherboards out right now that "Auto" overclock your chip for you (or others that Greatly Assist the overclocking process) so that many people completely new to overclocking can achive 3.5 Ghz freq speeds MINIMUM on air and I'm being very soft on that estimate. Most people using the Mobo assistance clocking methods get you well into the 4.0Ghz range easily with an aftermarket cooler (But you can achieve the 3.5 Ghz without it).
So having a chip that practically overclocks itself to 3.5+ Ghz on air for around $299, with a Multiplier higher than the previous chips and on top of that i7 chips seem to favor odd multipliers while overclocking instead of even ones and the i7 950 has an Odd multiplier at 23.
Drop the $299 for the i7 950 for an amazing chip at a great great price. Spend literally 2 - 3 hours total overclocking it with a decent mobo and it runs crazy fast. If you can't afford it pick up the i7 920 or i7 930 at a Micro Center for $199.
I hope that helps clear some confusion up and Overclock.net can be an invaluable asset in educating yourself about overclocking and what features you need to be aware of that you are paying or not paying extra money for in the Processor you are obtaining.
Let me give you guys some facts. When you compare which CPU is better for gaming, it really depends on what game you are playing.
In general, i5 7xx or i7 8xx will perform better than i7 920/930/950.
Today's most games do not even fully utilize two cores. Same with dual channel vs triple channel memory. Most games only require 2GB. Using triple channel memory setup for playing games that only require 2GB would not make much difference.
Now, even if the game requires more memory for games like Crisis, i5 7xx or i7 8xx can still perform better than i7 920/930/950.
i5 7xx: Advanced turbo technology on single core operation. no hyper-threading.
i7 8xx: Hyper-threading. dual channel memory setup.
i7 920/930/950: Hyper-threading. tripple channel memory setup.
Now depending on games, studies show that the hyper-threading technology that i7 has can reduce the game performances. I do not have direct reference to it but I will leave it up to you on researching that information.
But as I described above, i5 7xx series has advanced turbo technology on single core operations and i7's do not have that.
Because of this, i5 7xx usually performs the best in general games, and i7 8xx or 9xx performs the best when you play games that benefit from hyper-threading technology.
But like everyone agrees, there aren't much differences. But if you are using your system mainly for gaming, I recommend getting i5 750/760. This will last at least 2-3 years for playing mainstream games at close to max settings.
You can rebuild a new system after 2-3 years with the money you saved from going i5 750/760 instead of i7. There is no doubt that i7 9xx is more future-proof, but trust me, Intel will produce more i5 CPU's as well as more i7 even after they bring 6/8 core CPUs in the future. You can upgrade to a newer i5 CPU if you need to feel an upgrade.
FYI, if you are a CPU heavy overclocker, then I would recommend i7 920/930 because they have alot of rooms to increase your performance. But if you aren't heavy overclocker, then i5 750/760 still has good enough room for some moderate overclocking. I am personally against heavy overclocking because of its risks and extra cost on cooling and designing your rig for heavy overclocking.
When it comes down to the cost of building a rig, you can get i7 930 for $199.99 and i5 760 for $159.99 from Micro Center. There isn't much difference to the price but you have to get more expensive motherboard for i7 that uses LGA 1366 socket, and triple channel memory setup also can cost more even though you can still use dual channel operations.
There is a huge portion of the quality control aspect of the difference between these processors that people really overlook.
They make the better processors out of the materials that score higher on the stress tests etc. Basically a 92 is a 920 [even though essentially all the components are the same] because the materials that went into that 920 were not up to 950 or 960 or whatever quality control standards.
Sure they are all basically the same and you can clock the lower ones almost as good as the newer ones, but the better processor you buy to begin with means the better quality of material you start with period and the lower your temps will be.
You sir, are correct. An i7 CPU s quality depends on the wafer,and what part of the wafer it is cut from among other variables. That's the nature of Intels binning process and it makes sense if you read the article you linked. i7 has worked great for me so far (the 1366 version anyway) but I'm a little skeptical on Sandy Bridge from what I've read lately. Seems to me that they're packing too much on to the CPU. Do we really need DRM on a CPU? We'll see how it plays out I guess.
I have not done enough adequate reading on the sandy bridge processors to give any opinion yet, and considering I just purchased an i7950 when the prices finally dropped. I think I may save that bit of research for a far, far distant future that I may more thoroughly enjoy the one I just bought!
Unless Of course I fry this one sooner to be expected, but from the reviews thus far, I think I made a good selection