Dell T3400.. Do You Have DDR2-800 Memory?

That looks correct. There are two timings available (I guess this is in the bios) and you are using the 400Mhz timing.

With DDR2 you need 2 matched DIMMs to get the double-data rate of 800Mhz. If you have 2 DIMMs you should make sure they are in the right slots. They should go in slots 1 and 2 which are NOT next to each other on the last dell MB that I saw.

The slot numbers on the last Dell I saw were: 1, 3 and 2, 4

You also have ECC ram which I assume is why your timing is 5-6-6-18.

 

So maybe one of you guys could interpret all of this to this computer neophyte. What does it all mean?

OldTrader

 

Regarding ECC RAM... that's Error Correcting Code... there is also non-ECC.

As for the "timings", I guess the easiest way to explain it is that in processing data, the RAM does a few different functions... those timing number are the number of clock cycles to perform that specific function.

Some mobos allow the user to adjust timings and voltages. Overclocking enthusiasts try to make their computers run faster, and faster memory is part of that. Dell's do not allow these adjustmenst, so you have to be careful what RAM specs you're buying if adding RAM or replacing it.

Here's a link for more detail.

http://www.hardwaresecrets.com/article/26

 

I wonder if non-ECC would have different timing...??

 

Oldtrader, I got the exact same "timings" on my new Dell T3400 when I added 4 Gigs of the PC-6400 ECC RAM at 800 MHz at 1.8 volts made by Nanya.

(5-6-6-18 in the bios) and (6-6-6-18 in the memory).

By the way, my computer initially came with 1 Gig of PC-5300 Non-ECC RAM at 667 MHz. The "timings" were 5-5-5-15 with 1.8 volts.
Samsung too.