Is the CPU upgrade worth it without Mobo upgrade?

No. You won't gain anything by changing boards. Normal ram speed for the x58 is 1066, but the timings are actually a little faster with the slower fsb. You can try overclocking the 920 if desired, but I wouldn't raise the cpu or ram voltage. Just give it a try. The asus board is capable of it. If you don't want to overclock, look for the 950 or 970 used on craigslist, anandtech's for sale forum, or ebay. You may also find cheaper ram upgrades if needed; just buy it in threes.

U r mobo can handle that processor . increase ram then use ssd for os and softwares that make sure u get performance difference.

Two things:

It is my understanding that the i7-970 is a 32nm chip where the i7-920 is 45nm, that and the 970 is the next generation, thus there is improved performance above just the increase in the MHz of the chips. Is my impression correct or are those two factors simply what allow the higher speed, which overclocking the 920 can also achieve?

I have never overclocked, but... I am dealing with a development issue that is showing up on a i7-3770K that I have (not my machine, so I cannot install development tools on it) and other customer machines. I am thinking that I am dealing with a race condition that I am not seeing on my slower machine.

So the question, in the short term is... How to get my machine to preform like a i7-3770K?

Can I do that with overclocking or are there are others factors such as the chipset, etc, that will simply prevent me from really being able to duplicate the environment?

Looks pretty close in some benchmarks; it's a question of price.

http://www.amazon.com/Intel-i7-970-Processor-Socket-LGA...
$665

http://www.newegg.com/Product/Product.aspx?Item=N82E168... $320
http://www.newegg.com/Product/Product.aspx?Item=N82E168... $120 after rebate; total $440.

The 3770k upgrade is cheaper unless you find a 970 used. Go with the 3770k

Well, for some crazy reason, I really like the idea of my main system being either a 1366 or 2011, but now that you suggested the upgrade, I can upgrade my secondary dev machine from the Core 2 Duo to the 3770K.

The question remains, if I simply upgrade my current system to the i7-970, will it be preforming along the lines of the 3770K?

The one benchmark link shows the 970 about 10-15% slower, so in real world applications, you won't notice much difference. I would definately not spend $665 on a new 970 when your board is already outdated. Intel won't bring out any newer faster motherboard chipsets for any of the socket 1366 cpus, so why spend so much on a dead platform. Your current asus board is very good. Hold out for a used 970 cpu and offer about half it's original price, or about $300-325. I wouldn't spend any more. If you don't find one used, don't waste any money on upgrading it. It's not worth it. Actually, the best use of your 920 setup would be to sell it with the asus board for around $200-225 and apply the money towards one or two 3770k combos. It's similar to someone deciding whether to make a major repair on an older car or sell it and get something else. At some point, it makes no sense to put any more money into it.