3770 vs 3820

Build your own. A 21" monitor for graphic work is useless and both those prebuilts have poor quality parts.

What is your budget?

1600-1800 dollars
i am not expert in computers to be honest... but if u had those 2 options.. what would u choose?

Neither. I'd build my own or have one built. This would be what you want:

CPU: Intel i7 3770
MOBO: Asrock B75 Pro 3
RAM: Patriot IEM 16GB DDR3 1600MHz CAS 9
GPU: Depends, do you need workstation graphics or a standard Nvidia card?
SSD: Samsung 840 Pro 256GB
HDD: (Scratch drive) Seagate Barracuda 2TB
PSU: Corsair TX 750 v2
CASE: HAF XM
MONITOR: Dell Ultrasharp U2711

Win 8 or Win 7

Consider another SSD for a really fast scratch drive too.

so i am back to my same problem man
i was really confused about buying orginal one or to build my own pc....... i spent the last week looking forward building my own
and today i was convinced by a company that said the orginal is much better
   
i ll seach for the one u just wrote ... thanks alot

How is a pre-built better? They use poorer quality PSU's, locked down motherboards that don't offer the same feature set and the cases will fall apart if you fart near them. The above build has room to grow and expand. Pre-built's don't.

lol .... i dont think i ll fart next to them  
thanks alot.... i ll guess i ll wait a lil and search more before i buy it  

The first prebuilt has an X79 MB, which provides substantially better memory bandwidth if all four memory channels are used. Depending on the behavior of the listed programs, that increased bandwidth could substantially boost performance... or not. I would take a look at the most recent SBM that included a Z77 MB for the mid-range, and an X79 MB for the high-performance system, and compare their performance with the applications you list. Then, research whether your software supports Cuda, OpenCL or both (and how much), and figure out which GPU (if any) makes the most sense in light of that. If your software supports GPGPU well, then spend more on e.g. a AMD 7970 or NV 580/590 to make it fast. If not for what you want to do, then spend more on the CPU. And if the SBM benchmarks for your target software indicate that the X79 chipset provides an advantage due to increased memory bandwidth, then factor that in (assuming GPGPU support is not strong; otherwise, keep that money in the GPU).

Over time, you should expect to see increased workloads assigned to the GPU, so the benefit of e.g. 3820 or 3930 on X79 will decrease.

3770 is more powerful in all benchmarks I've seen.

Pffff don't believe everything that a salesman says. Their name is "salesman" for a reason, they try to sell their stuff, just that   Pre-bults are no longer special, even not good as a custom build i'd dare to say

The only advantages 3820 has over 3770 are higher memory bandwidth (due to more channels) and more PCIe lanes. With that though, you get the following:
- Much higher cost
- Higher memory latency
- Higher PCIe latency
- Questionable support for PCIe 3.0 data speeds

If you're going X79, either go 3930K (or better), or don't waste your money.

thanks alot guys
but in the offer in the link
what doest it mean 3 way Nividia SLI ???
will the offer give me 2 graphic cards or one ??? whats it kind ?