I wass thinking about ram upgrade to 6gb but will Dual Channeling work?
Dual channel will still work. Intel has something what I like to call hybrid dual channel (no idea what the actual name for the feature is).
The idea is very simple; for reach pair of RAM modules…
1) If the two modules match then dual channel is enabled for all the RAM.
2) If the two modules do not match, dual channel is enabled up to the maximum of the smaller memory module.
In the case of 4GB+2GB, we would be looking at #2, where 2GB of the 4GB chip would operate in dual channel mode with the other 2GB module, and the remaining 2GB on the 4GB module would operate in single channel mode.
That said, even if you're stuck with single channel for everything, the benefit of having more RAM for your work heavily outweighs dual channel bandwidth.
About Intel 320 im looking at it but also loked at others OCZ vertex 3 and Crucial M4 almost same price point. But maybe Intel 320 hass constant write/read speed to reach max 1.5gb? im still googling...
You only have a connection interface that maxes out at 1.5Gbps; the Intel 320 is a solid performer, with an excellent warranty, and definitely fulfills your performance needs.
Sure it may not be as fast as new drives like the Vertex 3, but you can't utilize the performance benefits of a faster drive.
If you wish, you can of course purchase a faster drive, but some controllers like the Sandforce one in the Vertex 3 have compatibility issues with slower interfaces.