gigabyte GA-EP45C-DS3R - RAM upgrade

[Sew]

Gigabyte official site specification http://www.gigabyte.pl/products/page/mb/ga-ep45c-ds3r_10/specs/
2 x 1.5V DDR3 DIMM sockets supporting up to 4 GB of system memory
4 x 1.8V DDR2 DIMM sockets supporting up to 16 GB of system memory
Dual channel memory architecture
DDR3 1600/1333/1066/800 MHz
DDR2 1066/800/667
questions:
1. Is it possible to have 4GB in one DDR3 RAM memory card?
2. Is it possible to have 2x 4GB DDR3 RAM memory cards?
3. Is it possible to have both DDR3 and DDR2 at one time? (I have one 2GB DDR2 DIMM and I would like to buy DDR3 DIMM).
Thanks in advance,
Sew

[dmdilks]

Installing a Memory
Populating DDR2 and DDR3 memory modules simultaneously is not supported.

You really are better off to use DDR2 memory because you can install more.

You really are not going to see a big jump in perforumance from DDR2 to DDR3 memory.

Plus it is what CPU you are going to use too. That will support the memory you are using.