Can Optiplex 780 support DDR3-1600?

Usually, the faster memory will work.

There is no support for DDR3 2000 (PC3 16000) and the bus will never run at that speed.

There is no overclocking and the FSB is determined by the cpu and chipset so no and no.  You cannot use Registered Ram and faster ram will not run faster it will clock down to 1066 or slower depending on the cpu.  Furthermore 4 rank high density ram does not and will not work.  Max dimm size is 4 gigs and max ram is 16 gigs aka 4 x 4 gig low density 2 rank ram.  Buffered, Registered, ECC ram is not possible nor is 32 gigs of ram total. So while DDR3 1600 (PC3 12800) will work it will not run faster with a slower FSB cpu.  I recall that when I put in a 1333mhz fsb cpu the ram still ran at 1066 mhz.

 Dell OptiPlex 780 MT Desktop Computer- Intel Core 2 Duo E7600 with VT (3.06GHz, 3M, 1066MHz FSB) for example.

 Regulatory Model (Mini-Tower): DCSM or DCSM1F
Regulatory Model (Desktop): DCNE or DCNE1F
Regulatory Model (Small Form Factor): DCCY or DCCY1F
Regulatory Model (Ultra Small Form Factor): Regulatory Model D01U / Regulatory Type D01U001

Max bus speed and Ram Speed for the chipset. Aka 1066 is max regardless of the cpu FSB. Note the RAM TYPES in the INTEL spec for the chipset.

http://ark.intel.com/products/36527/Intel-82Q45-Graphics-and-Memory-Controller-Hub

• Max Data Bus Speed 1333 MHz
• Chipset Type Intel Q45 Express

Thank you, rdunnill and SpeedStep!

Based on your information, DDR3-1600 can run on Optiplex 780, either at speed 1066 or 1333, which is fine with me. I will go ahead and buy DDR3-1600. Thanks again.

Thank you, rdunnill and SpeedStep! Based on your information, DDR3-1600 can run on Optiplex 780, either at speed 1066 or 1333, which is fine with me. I will go ahead and buy DDR3-1600. Thanks again.

While this is true the VOLTAGE, DENSITY, TIMING,  ECC OR NOT ECC, REGISTERED, 4 RANK VS 2RANK or 1RANK is not trivial.  4Rank ram WILL NOT WORK,  BUFFERED Ram WILL NOT WORK,

REGISTERED Ram WILL NOT WORK.

HIGH Density Ram WILL NOT WORK.

Based on your information, DDR3-1600 can run on Optiplex 780, either at speed 1066 or 1333, which is fine with me. I will go ahead and buy DDR3-1600. Thanks again.

Speedstep just reminded me that single-rank memory can be a problem, and manufacturers are quietly substituting it for the older dual-rank products.

I encountered this issue a few months back; the older G41 quad-core system would not boot with a pair of brand-new DDDR3 2x4gb DIMMS (single-rank), but worked well with an older pair with the same part number (dual-rank). You may want to focus on memory specifically validated with your model.

The other issues in the DDR3 realm are that some are not pairs but rather Tri channel Ram like the precision T3500 with 6 slots.  And you cant mix ranks.

Crucial is selling DDR3-1600 RAM for this system. And if they recommended it, they guarantee it works, or they take it back.

So that might be a way to test it out with no risk to you. :emotion-5:

So that might be a way to test it out with no risk to you.

Yes.

Yes, but the speed of ram will decrease to 1066mhz