I am about to upgrade my DELL XPS 8900 and add 64GB memory to it, I have found that the montherboard of DELL XPS 8900 does support that kind of capacity.

However I have a hard time picking up the right RAM. DDR4 is supposed to be better than DDR3, but other factors seem to weigh in.

Like some examples shown below, DDR3 is not necessarily cheaper, and appear ECC is a plus factor too: #2, Kinston's DDR3 is more expensive than #1, DDR4 from Curcial, and the #3 is the most expensive, can ECC alone explain the price gap to #1? And do these difference translate into a perceptible performance difference?

From Crucial official site:

  • Crucial 64GB Kit (4 x 16GB): DDR4 PC4-21300 • CL=19 • Dual Ranked • x8 based • Unbuffered • NON-ECC • DDR4-2666 • 1.2V • $567.99

From newegg.com

  • Kingston 64GB (4 x 16GB) 240-Pin DDR3 SDRAM ECC Registered DDR3 1600 (PC3 12800) Server Memory Model KVR16LR11D4K4/64 $736.53

From newegg.com

  • Crucial 64GB (4 x 16GB) 288-Pin DDR4 SDRAM ECC DDR4 2133 (PC4 17000) Server Memory Model CT4K16G4RFD4213 $806.91
  • 1
    You cannot put DDR4 in a PCthat uses DDR3 and vice versa. ECC is for servers. Make sure you have enough slots and get regular ram of the same sort you have now (ddr3/4)
    – Journeyman Geek
    Aug 16, 2017 at 3:52
  • Thank you for the suggestion. I looked up xps spec and it appears to support ddr4
    – J.E.Y
    Aug 16, 2017 at 4:09
  • 1
    The one from Newegg is more expensive and slower. The PC4-xxxxx numbers are the theoretical maximum bandwidth figures for the sticks so you would be paying $200+ more for memory that is (in theory) 4000MB/s slower. Check your computer manual for the maximum speed memory your system supports and buy the fastest and cheapest you can.
    – Mokubai
    Aug 16, 2017 at 6:52

1 Answer 1


The best RAM depends on your needs/requirements.

DDR 3 is probably not what you want. It's generally slower and significantly more power hungry then DDR4 (40percent is bandied about - probably not too big a deal on a deskop though)

ECC is more expensive because it's a lot more reliable and requires extra chips for reliability and calculation. If you are using it as a server this is probably a good idea - for a gaming rig or workstation it's probably unnecessary. If you are running a ZFS filesystem (if you don't know what it is, you aren't), you really need ECC. ( Unfortunately regular memory can very, very occasionally have a bit flipped due to cosmic radiation (or going faulty) - the question is what is the value of protecting against that - good quality non-ecc memory is still subject to bit flips.

Most desktops would use the cheaper DDR4 memory, most servers the ECC memory, and yes, a good part of the price difference is because it's ECC.

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