Much less than you'd think if you are willing to go with 6TB only. The 128GB modules are awfully expensive but the other day I saw 64GB modules at $600 https://

Much less than you'd think if you are willing to go with 6TB only. The 128GB modules are awfully expensive but the other day I saw 64GB modules at $600 https://memory.net/product/s26361-f3843-e618-fujitsu-1x-64gb-ddr4-2133-lrdimm-pc4-17000p-l-quad-rank-x4-replacement/ https://memory.net/product/s26361-f3843-e618-fujitsu-1x-64gb... here. So that's ~39K for 6TB of RAM. The relevant Supermicro server (4048B-TR4FT) with four E7 CPUs is ~14K http://www.thinkmate.com/system/superserver-4048b-tr4ft http://www.thinkmate.com/system/superserver-4048b-tr4ft comes with 32 4GB modules which is a waste but oh well, it's a very small loss compared what it would cost to buy 6TB at a server seller like this. So you are looking ~53K for the server, CPU, 6TB RAM, you will need a little storage as well, so perhaps ~60K for a 6TB 4U server. In closing, let me remind you that a mere two decades ago, Microsoft launched the Terraserver which was a demonstration of a server with a terabyte of storage and it was very big news. Now we are here with a machine at the price of an ordinary F-150 truck or so which can hold the 5TB uncompressed data of the Terraserver in RAM.