this ram should work in my pc but it doesnt - why?

[tan8856]

Hi

I have a dell inspiron 580 which came with 4 x hynix 1gb 1333mhz ram
I wanted to upgrade so I bought 4 x hynix 2gb 1333mhz ddr3 sticks (second hand).
When I put the new sticks in the pc wont boot up and does 2 beeps which means 'ram not detected'.
Ive tried 1 stick of the new ram in each of the slots and various stick combinations in various slots but always 2 beeps. When I put the 1gb sticks back in the pc works fine so its not the slots thats the problem. It must be the sticks. But why are all of them not recognised? Surely they cant all be dodgy? Ive upgraded ram on other pc's with no issues. The sticks are definitely pushed right in. The pc manual says 4 x 2gb is fine. I stuck with same brand - hynix. I stuck with 1333mhz although i cant see any way of telling the mhz off the text on the sticks. I assume both the 1gb and 2gb are ddr3?

Im attaching pics of a) 1 of the 1 gb sticks b) the 2 types of 2gb sticks

thanks

 

[flameport]

The 2GB items are registered memory, the others are not - 10600R compared to 10600U.
Registered memory is typically used in servers and high end workstations, and unless the motherboard specifically supports that type of memory, they will not work.

 

[tan8856]

The 2GB items are registered memory, the others are not - 10600R compared to 10600U.
Registered memory is typically used in servers and high end workstations, and unless the motherboard specifically supports that type of memory, they will not work.

thank you!