You ask a lot of questions, but then again, you are planning on dropping a lot of money on this, so it's understandable.

It took the better part of five years for quads to become the standard for any system that requires the extra processing power. Even today, most games run competently on duals, not that I'd recommend one to anyone building a gaming PC, even on the cheap.

Hex cores, barring AMD systems (who have used hex core designs in CPUs available for about or less than $300 simply because they provide less performance per core than their Intel counterparts) are pretty much for workstation or extreme high end gaming PCs currently. Gaming PCs with Intel hex cores don't even see much, if any boost in performance for games simply because no games are optimized to utilize the extra cores.

Even with the current rate of progress due to Moore's Law and all the R&D that goes on to keep the trend going, I don't see hex core systems being common for years, simply because there are limited applications that take advantage of the extra processing power.

For 3D artists who do a lot of rendering, hex cores pay off instantly. Same for video editors who do regular video encoding. Add post processing and video effects in apps like Adobe After Effects and the extra processing power will be put to good use. Photo editing generally doesn't require the same level of processing power barring professionals and digital artists who work with huge files. Music production requires less processing power, but with high end editing systems, it helps.

So maybe the question should be how long are you planning on keeping this system in the state it will be in once you build it, followed by when are you planning on doing a major upgrade like a CPU swap.

Personally, even if I was spending $4000 on an all new system build today (which in the US would pretty much give me carte blanche to build any configuration I wanted), it would be so with the acknowledgement that in no less than 2 years, there will be much faster components available at the same price or less.

So maybe the rule for anyone doing a pricey build is that they should only be doing it for a system they'll only be using for 3-4 years tops barring any major upgrades (I say 2-3). Anyone who justifies an expensive (for their budget) build with the rationale that it will last them forever (or even 5 years) is setting themself up for a disappointing shot of reality. If you're comfortable with that, then buy the best components available today that you can afford.

Otherwise, build a system on an i7 2600/2700k and you'll probably feel a lot better when you build a new system in another 2 years.

For me personally, if I needed to build a moderately priced system from scratch that gave me the best performance for my dollar, who works extensively in Maya (3D artist/animator) and works regularly with HD video (videographer) and digital photography (file sizes in the hundreds of megabytes), I'd build one on a 2600k and use it for the next 18-24 months while waiting for the upcoming Ivy Bridge processors. The only drawback is that I wouldn't be able to re-use the LGA 1155 motherboard (a $200+ part) and RAM, which is nothing at $85 for 16GB in the US currently. Add the $300 2600k and that's really only about $600 worth of parts that I'd be replacing, which is nothing over the span of even 18 months.

If I went with an LGA 2011 motherboard today (cheapest being a $300+ part, closer to $400) my cheapest CPU option (unlocked since I'm an overclocker) is a $600 Core i7 3930K. Add in another $85 for 16GB of RAM and that's about $1,100 worth of components to be replaced, meaning I'd probably be using that set up for quite a bit longer.

For the record, I did a rebuild in early 2010 based on an i7 920, LGA 1366, 12GB RAM and currently do most of my Maya (not rendering) and video editing work on an i7 quad MacBook Pro. The PC is currently only used for rendering and the occasional game so I won't bother to upgrade until I need more processing power, which will probably be to an Ivy Bridge CPU on an LGA 2011 motherboard with 32GB of RAM.

Looking at your requirements and things you want to do. I believe the choice should be obvious.

You need to get liquid cooled Quad SLI GTX 580s minimum...or you may as well just get an Atari 2600 and live in a cave...with mountain goats. :)

Or...

http://www.newegg.com/Product/Product.aspx?Item=N82E16819103961

I'd never build a productivity PC with an AMD CPU.

It's not that I have anything against AMD (all but one of my VGA cards are ATI/AMD), but considering that there aren't any professional grade workstations using AMD CPUs is pretty much saying that at best, they are an inexpensive alternative to Intel and the benchmarks support this.

http://www.tomshardware.com/reviews/fx-8150-zambezi-bulldozer-990fx,3043-20.html

does the 2nd PS-E slot not being 16x reduce the speed and performance

or does it only need 16x in total,8x in one and 8x in other

there should be enough PCI-E slot to accomodate audio card,wifi,bluetooth card

about ram lanes,is it necessary to ram in specific amount or is it just to increase performance?

for example:if i buy 8gbs of ram and cpu support triple channel.and suppose 8gbs are divided into 4 2gb memory.will the 4th memory not work or perform as well?

So you will want a high end GPU then

1080p is pretty heavy so you will need a lot of HDD, RAM and a good CPU

GPU can help but not all programs support it so it may not be a good idea to relly on it to heavily especially with editing a lot CPU is still really important. It may be worth checking what programs you will be using.

It does make a difference but it's not huge and offers diminishing returns higher you go, usally you are usally better spending money on other things tho I wouldn't go below DDR3-1600 for a high performance PC like you are building.

so which CPU 2600K or extreme

also remember 2600k can be overclocked

if it will do with overclocking,how fast does spu run out as in diminish life cycle of a cpu

also suggest ram,i was gonna buy 10-12gbs of it

and wat do you think of SSD as system drive

or ssd as cache(checkout intel Z68 mobo,they have ssd cache thing)

how should i deal with cache?

Depending on price (I am not sure how much they are where you are) I would probably lean towards the 3930k considering what you want it for and that you want it to be reasonably future proof. check http://www.xbitlabs.com/articles/cpu/display/core-i7-3960x-3930k_10.html#sect0 and http://www.tomshardware.com/reviews/core-i7-3930k-3820-test-benchmark,3090-7.html for an indictaion on the advantage it offers, but it will probably end up being a bit to expensive for the advantage for you.

If you do decide to go with the 3930k you will have quad channel RAM so I would suggest 4x4GB for a total of 16GB, otherwise I would say that 8GB would be the absolute minimum for a video editing machine that will be sticking arround for a while ~16 would probably be the sweet spot,video editing is very RAM heavy from what I know so I wouldn't skimp to much. Tho RAM is easy to upgrade so if you want to save a bit in the short term and upgrade the RAM later that is easy to do so if it comes down to cutting CPU/GPU or adding more RAM I would probably cut the RAM and get more later. If you are using after effects tho you may want to consider 24GB+ as that is a monster for RAM.

I haven't really had much experiance with SSDs so I would deffer that to someone else.

u didn't answer the ram vs channel question?

if ram is put in for exmaple,if the processor supports 3 channel and i put in 4 ram sticks,will it effect performance

3930x costs me $1200 and 3960x costs me $1400 in india,is it worth it or will intel bring 6core processors for $300 in 1.5-2 year time

how much ram compensates in encoding time for cpu power

does cache has to do anything with performace time as i can buy an ssd if needed,a small one