Confused about memory restrictions on GA-P31-DS3L motherbo..

I'm about to build a system based on an Intel E6750 processor and a
GA-P31-DS3L motherboard. I currently have two 1Gb sticks of Corsair
TWIN2X2048-6400 RAM to go in it. I'm also considering installing the 64-bit
version of Vista Home Premium, in which case I will purchase a further two
sticks of the aforementioned memory. However, I'm puzzled by a couple of
statements in the motherboard's specs.

The first is :

"Because of chipset limitations, do not populate both DIMM sockets of the
same channel (e.g. DDRII1 and DDRII2), or populate 4 DIMM sockets with
double-sided memory modules to prevent system's failure to start or
incorrect detection of memory modules."

The second is:

"Because of chipset limitations, when using FSB 1333 MHz CPU with populating
all DIMM sockets, memory frequency will be reduced from the original, and
system instability or incorrect detection of memory module may be occur."

I'm probably being thick here, but I can't quite work out the ramifications
of this. Does it mean that although Gigabyte have provided four memory slots
they can't all be used simultaneously? Also, if I do populate all of them
with the memory mentioned above, what can I expect to happen in practice?

Any and all ideas gratefully received.

Steve Silverman