ram compaire

thanks,for your urgent replay as you see the ram specification  is different in capacity (4 & 16) and in data width (x4 & 8x) and in rank (single & dual )

(16GB RDIMM, 1333 MHz, Low Volt, Dual Rank, x4)

(4GB RDIMM, 1600MT/s, Low Volt, Single Rank, x8 Data Width)

so if i need to buy one of them what should i buy to get high performance 

Hello

Low voltage DIMMs typically operate at 1.35 volts. You would need to check the specs of the DIMMs to be sure. If they both operate at 1.35 volts then you should get the same efficiency out of both. You could look at the 16GB DIMM as being more efficient because it would require 4 of the 4GB DIMMs to equal the amount of memory.

If you were to compare energy cost of the 4GB DIMM versus the 16GB DIMM then they would likely be identical if they are the same voltage.

Thanks

There are a lot of factors that go into choosing which memory will perform better. Just putting those two side by side the 4GB DIMM should outperform the 16GB DIMM.

How the DRAM is structured on the module should have little, if any, affect on performance. The two main considerations for performance are the memory speed and how the memory is spread across the channels. Having the memory modules spread across the channels provides more bandwidth and available MHz. Two DIMMs of a lower MHz would likely outperform a faster single DIMM.

Thanks