Memory ID-ECC or non-ECC?

Newmaven said:

I thought I had 16GB of RAM, but two of my four cards are only 1 GB. I'd like to replace them but I can't recall whether I have ECC or non-ECC RAM. Is there an easy way to check?

What I get from this is either the 2 x 1GB modules are bad or the slots they are in are bad. I'd remove those 2 x1GB modules [computer off, unplugged from power and wait a few minutes before doing it] then power up and check again. Also check that the remaining 2 8GB modules are in the same color slots so as to gain dual-channel performance, the slots usually alternate and may be numbered, use 1 and 3 or 2 and 4.

Memory modules come in 1GB, 2GB, 4GB, 8GB, 16GB, 32GB, etc., capacities, best to match in pairs.

If working properly your four modules should add up to 18GB, kinda odd but I have a Notebook with 6GB [4GB plus 2GB] and have seen a Desktop with 12GB [8GB plus 4GB]. Lots of memory is fine but I see times where matched modules are more stable.

Here's a list of the 6GB RAM in my Dell Optiplex 755 used as an IP/Insider Preview computer, it was created by Piriform's SPECCY program:

RAM
Memory slots
Total memory slots 4
Used memory slots 4
Free memory slots 0
Memory
Type DDR2
Size 6144 MBytes
Channels # Dual
DRAM Frequency 334.8 MHz
CAS# Latency (CL) 5 clocks
RAS# to CAS# Delay (tRCD) 5 clocks
RAS# Precharge (tRP) 5 clocks
Cycle Time (tRAS) 15 clocks
Bank Cycle Time (tRC) 20 clocks
Command Rate (CR) 2T
Physical Memory
Memory Usage 49 %
Total Physical 5.50 GB
Available Physical 2.78 GB
Total Virtual 7.50 GB
Available Virtual 4.26 GB
SPD
Number Of SPD Modules 4
Slot #1
Type DDR2
Size 2048 MBytes
Manufacturer Patriot Memory
Max Bandwidth PC2-5300 (333 MHz)
Part Number PSD22G6672

Slot #2
Type DDR2
Size 2048 MBytes
Manufacturer Patriot Memory
Max Bandwidth PC2-5300 (333 MHz)
Part Number PSD22G6672

Slot #3
Type DDR2
Size 1024 MBytes
Manufacturer Samsung
Max Bandwidth PC2-5300 (333 MHz)
Part Number M3 78T2863DZS-CE6
Serial Number 82199C0A
Week/year 45 / 07

Slot #4
Type DDR2
Size 1024 MBytes
Manufacturer Samsung
Max Bandwidth PC2-5300 (333 MHz)
Part Number M3 78T2863DZS-CE6
Serial Number 82199BFA
Week/year 45 / 07