Can Optiplex 780 support DDR3-1600?

Question

I have an old Optiplx 780 (late 2009). I know the manual says it only supports 1066 and 1333, but I remember seeing somewhere that with BIOS upgrade it can support DDR3-1600. Is this true? The reason I am asking is that it is easier to find a cheap DDR3-1600. Thanks for any information!

Answer 1

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
Max Memory Size
16 GB
Memory Types
DDR3 800/1066, DDR2 667/800
Max # of Memory Channels
2
Max Memory Bandwidth
8.5 GB/s
Physical Address Extensions
36-bit
ECC Memory Supported 
No