The factor you miss is that the mainboard is not FSB based on an i7 system, thus the multiplier is what you are actually overclocking.. as such when you adjust FSB on older systems, it is the multiplier and frequency that you are adjusting to gain speed.
I7's on the 920's you can adjust the frequency but the multiplier is locked, thus gimping OC builds..
On the i7 970 and above series, the multiplier is unlocked and the frequency is unlocked so you can actually OC to well over 5 Ghz. If using stock cooling (read fans / air cooling), then you can hit 4.6Ghz with a comfortable heat threshold limit given that the 975 CPU has a max heat limit of 130 W, where the 920 has a max heat limit of 90 W. I'm not even going into Standard CPU 920 vs Extreme 975 performance factors or processing capabilities, etc.. the 975 series blows the doors off anything on the market ATM next to the actual 980 series wich is OC capable of 1.3 times the 975 speed limits. for Cost Effectiveness, the 975 is the best buy on the market ATM.
Besides, I am thinking long term not short term.. the 920's are considered a mid grade shipset currently.. so that means next year they will be base model chipsets that you can buy at Wal-Mart / Best Buy..
With the OC capabilities of the i7 975 chipset.. the system will be viable for any software coming out for the next 5 to 8 years without upgrading, just use a simple OC to hit a comfortable stability for any new software.
I mean think about it seriously.. say a new game / program comes out requiring a 3.6 Ghz CPU.. well you will have to either upgrade or Overclock in order to use it.. on a system that is already OC'd to 3.8 GhZ, some instability may occur due to actually pushing the CPU to that speed 100% of the time playing the game..
Now with an i7 975 with the appropriate board, say 4 years from now, a program comes out that you really want for your computer and it requires a system with 4.2 / 4.4 GhZ requirements.. what are you going to do.. buy a new mainboard and a new CPU costing you about $800 on top of what you paid on your old board which was what $675.. so your overall cost for old board / cpu + new board / CPU = $1475 compared to spending $1250 now for a mainboard / CPU that can handle any program coming out with requirements up to 5.4 Ghz (i7 975 OC'd on water cool)... where the 920 would have already been obsolete 2 years prior.
I understand you are looking at Cost vs performance.. however so am I... You are looking at the here and now or the next year or so.. I am looking at 5 to 8 years down the line and removing the need to upgrade each year (Except maybe Video Cards).
Anyhow.. just letting you know where I am coming from.
I must disagree, anyone that knows how to OC knows how to lower operating frequencies of ram and chipset and only raise the CPU speed, mutli lock does impose a limit but not a large one. Lower your ram divider and if you have to chipset divider. Also ocing on stock cooling is the stupid idea you could do, you should never do this, ever. Go to any respected tech site and say your running an i7 @ 4.6 on stock and they will laugh at you and demand proof for the simple reason its not only impossible unless you live in the artic but also foolish. But also no computer will get you 8 years if you plan to do more than email and word prosessing its that simple. My old system ran an Athlon 64 3500, that was bought when it came out, It lasted from 2004 till 2009 thats 5 years and by then it started to feel rather old and slow. If all your doing is word processing and email you can use a Pentium3 and 512mb of ram with windows XP and do just fine. Just because a CPU is supposed to last a minimum of 10years in lifetime of the silicon doesnt mean they expect them to be fielded that long as a primary CPU.
Actually, I'll call you out on that one. IF you stick with the games that came in the same period of the computer (so for my 2000 comp, which actually still has millenium...BUT doesn't go onto the internet as it's simply not secure enough with that anymore) you may have to replace a fan or power supply, but your computer CAN last that long and do the games of the period too. The difference is the components. If you have a Pentium or Intel from that many years ago...they actually are EXCELLENT quality. Of course you can't overclock it too much...THAT'S WHY you run through the processors so quickly. As for Athlons...they were ALWAYS junk...but cheap junk so that you can get more for your money in the short run.
That's important if you are going to keep up with the latest and greatest upgrades, and hence a cheap processor that you're going to replace in six months to a year doesn't really matter anyways...but for durability you NEVER go with an athlon. I have a Pentium (I think it's an original even, I'll have to buzz it up) on a Gateway from 1997 that I got second hand in 1999 (first computer I ever played SFC on actually) that has a 3 CD changer and still runs fine to play any of the older games. It still even has Win 98 on it!
My main browsing computer for internet actually HAS had more problems, had to replace the motherboard twice (in just the past few months actually, once from it just getting old, the other from something that actually peeves me off), the Vid card has been upgraded, and running XP (refuse to get WinVista, though the constraints with not being able to play any new PC games has me jumping at the bit to get Win 7 almost the day it comes out along with a top of the line new computer...and I'll be getting a Pentium with that one too).
I've also had Athlon processors, and I've only had ONE that's actually lasted more than 2 years of abuse from me. I would suppose I'm hard on them, I kill them quick. I think they average about a year and a half lifespan with me...they overclock, but I think Pentium's do it better. However, perhaps the current crop is different, as I said, I haven't gotten a new computer for around 3 years now...which is ANCIENT in computer terms. Just refused to get into the entire WinVista thing...which makes my computers currently ancient in terms of what they can do.
If you're experience is with Athlon's however, I'd say half the problems with getting a computer to last...or at least the processor, starts right there...
In my (I'll admit) over arrogant and presumptuously jerked and pompously foolish opinion.