8 GB motherboard

There are motherboards to support up to 32GB RAM,which socket are you considering ?

Wow...that would be a lot of RAM - you might try to look into server boards if you'll need something like that.

I agree with Maziar - we'd need more info to help advise.

only Intel 775 as of now  

i believe server boards do not come with multiple PCIe x16 slots unlike NVIDIA 680 SLI ASUS motherboards

i need at least three PCIe x16 slots and since we will be dealing with a lot of fast refreshing financial data the more RAM the better,

if i talk about the most ideal setup i think my minimum goal will be at least a max capacity to increase RAM up to 48GB as 8GB x 6 as of now.

i really do not want to waste these slots with 2GB or 4GB sticks,

the higher capacity utilization the better

even x58 desktop boards are only offering single 4GB single stick compatibility in a single slot. which gives them a max capacity of only 24 GB

and i could not find any ASUS 775 board with more than max 8GB  

Just how much data are we talking about? My cousin is a trader (and no, she never made "vaporware" investments, just to be clear) and she has to process data from markets all over the world. Her desktop AFAIK "only" has 4GB, and it's proven fast enough.

Also, what do you need the multiple PCIe x16 ports for? If you're trying to build a multi-display setup, you can always just shell out for a more powerful card that can drive many monitors on its own.

one cannot trade using multiple applications without multiple monitors

and its the watch lists that require that extra huge RAM since all that data never downloads on the HDD,

all those watch lists such keep refreshing in the programmes .exe kernel and they therefore reside and refresh within RAM only,

4GB RAM is barely sufficient for 400 tickers in just one app