What does "32GB(8Gbx4DR)" mean in the dumped RAM info?

The x4DR fits within the techspecs and probably Points to the dualrank "feature" of this particular RAM:

That's Correct. This specific naming convention is as follows(each vendor differs slightly):

[32GB][8Gb][x4][DR]

[DIMM_TOTAL_SIZE(in gigabytes)] [DRAM SIZE(in gigabits)] [number of data bits per dram (column width)] [number of ranks]

32GB = (8 * 16 * 2) / 8

8 gigabits * 16 chips (drams) per rank * 2 ranks = 256 gigabits

256 gigabits / 8 = 32 gigabytes.

The number of bank resource a DRAM contains (density) is internal to the DRAM and not consequential here. It is factored into [DRAM SIZE(in gigabits)].

For different DRAM width of the same density:

a x4 will contain twice the number of bank resources of that of a x8

a x8 will contain twice the number of bank resources of that of a x16

there is a performance advantage to having more bank resources per dram, since a dram can only have one page (or row) open per bank at any given time. In general, a x4 will perform better than a x8, which will perform better than a x16 (all other factors being equal) due to pipelining of transactions performed by the memory controller. This is because it takes time (latency) to open a page (activate) and close a page (precharge). You can effectively double the number of bank resources on a channel by adding a rank, but this is less beneficial than doubling the bank resource of the dram due to the fact that only one rank can communicate on the bus at any given time.

-Paul K