How to Add Memory to Dell Optiplex 790

• 

  scrimshaw on 02/04/2016 - 22:02

  +3

  So could I just buy 1 4gb memory to put my total up to 8gb?

  You could. But be aware you will not get dual channel memory — dual channel mem works when two, or four, slots are filled with the exact same types of memory. For the best mem bandwidth performance, fill remaining 2 empty slots with 2GB of memory.

  if you chuck in a asymmetrical setup, you'll be using single channel mode, this is around a ~5 percent decrease in memory bandwidth performance. Not a big deal though. Gamers, mainstream users, and office users shouldn't care. The ones who should care about memory performance are video editors and encoders.

  According to Intel:

  • Rules to enable dual-channel mode

  To achieve dual-channel mode, the following conditions must be met:

  > Same memory size. Examples: 1 GB, 2 GB, 4 GB.
  > Matched DIMM configuration in each channel
  > Matched in symmetrical memory slots
  

  Configurations that do not match the above conditions revert to single-channel mode. The following conditions do not need to be met:

  > Same brand
  > Same timing specifications
  > Same speed (MHz)
  

  The slowest DIMM module populated in the system decides memory channel speed.

  • 

    [Deactivated] on 02/04/2016 - 22:43

    Great information. Thanks for your help.

• 

  Edsanwong on 03/04/2016 - 09:13

  Awesome answer and explanation scrimshaw..!

• 

  [Deactivated] on 03/04/2016 - 09:19

  depending on your budget id upgrade all slots to 4gb each totalling 16gb

  crazy not doing this in 2016

  ddr3 is cheap as chips specially at 1333mhz

  although id consult your manual for this before doing it

  • 

    [Deactivated] on 03/04/2016 - 09:51

    I am trying to do this very cheap, so probably adding 4gb. Manual says 4gb per slot, so I guess I could go to 16 if I found it cheap enough. Thanks.

• 

  [Deactivated] on 03/04/2016 - 09:49

  Can anyone confirm if this is compatable? It is $28 for 4gb total, which is the cheapest I have found.

  http://www.msy.com.au/pc-components/9264-patriot-signature-4…

  specs:
  PC3-10600 (1333MHz) dual Data Rate
  240-Pin Dual in-line memory module
  Non-ECC Unbuffered
  2 Rank Double-sided module
  7.8US Refresh Interval (8192 CYCLES/64MS)
  1.5V Power Requirement
  Auto and self refresh capability
  PCB height: 1181(mil)
  Serial Presence-Detect (SPD)
  100% Tested
  RoHS Compliant

  My current memory reads: samsung 2gb 1rx8 pc3-10600u-09-11-a1.

  thanks.

  • 

    donnot on 03/04/2016 - 12:49

    I have a 790 and bought this stick to use http://www.msy.com.au/home/13316--kingston-hyperx-fury-blue-…

    Have it combined with 2x Samsung 2GB sticks that came with the machine and it runs great.

    • 

      [Deactivated] on 03/04/2016 - 15:58

      You have 1 or 2 of those? So when it says 1600mhz, that just reverts to slower 1333mhz?

      Have you tried installing windows 10 on yours?

      • 

        donnot on 03/04/2016 - 16:04

        Yes, I installed Windows 10 using a USB drive (free media creation tool) and to activate it I used the Windows 7 pro key that was on the case sticker. I have 1 of the Kingston sticks and 2x 2gb Samsung ones that came with the machine.

        The memory is underclocked to match the other 2 sticks at 1333MHz.

      • 

        [Deactivated] on 03/04/2016 - 16:08

        @donnot:

        Thanks. I was assuming there would be no issues updating to windows 10. But the shop guy was trying to convince me I would have problems. Thinking about in now, I suspect he was trying to upsell.

      • 

        donnot on 03/04/2016 - 16:18

        @Gofast:

        Here's my ram arrangement anyway

        http://imgur.com/AzsqdSm

        You might have to move around the sticks between the 4 slots to get it to work, but I haven't had any problems. Tried 1x Samsung 2gb alongside the Kingston with no issues.

      • 

        [Deactivated] on 04/04/2016 - 17:00

        @donnot:

        Purchased the msy memory I linked. All working without issues thankfully.

        Can you tell me what the Radeon 5450 did for your system? Where did you see improvement? Thanks.

      • 

        donnot on 04/04/2016 - 17:39

        @Gofast:

        The system initially came with 2x 5450 cards installed. The main improvement would be gaming (just light gaming such as minecraft etc). Outside of that, for what I used it for there wasn't much of a benefit. Would also potentially help with video playback but I don't have any figures on this.

        Have since replaced them with a Quadro 600 for some basic design/CAD work and light gaming.

• 

  [Deactivated] on 04/04/2016 - 06:50

  I have the same desktop.
  It had come with 2gb ram though and I bumped it to 4gb which was easier but a simple process.

  Just double tripple check the ram is in correctly and everything should work.