PC not recognising memory

[kimpossible]

I've just swapped out the 2 x 512MB memory on my PC for 2 x 1GB - however it only appears to be recognising 1GB. When I think about it....it only recognized 512MB previously.





Any ideas why?

[slaughteredlamb]

I may be wrong but I'm sure I came across this a couple of years ago and IIRC, If you are using DDR RAM then you must use the first slot of each bank with the exact same spec DIMM. Or to put it in laymen terms put 1x 1GB DIMM in the first slot (usually Slot Zero) and the other 1GB DIMM in the 3rd slot.

You only use the 2nd and 4th slots when you install more than 2 DIMMS and again these slots need to match each other but they don't have to match those in slots 1 & 3.

[kimpossible]

There's only 2 slots on this PC though.

[Stealth]

The online specifications say it supports 2GB so your safe there.

# Although unlikely its worth having a poke around the BIOS settings for answers.
# Could the DIMM be dead? Try using 1 DIMM and see if the PC boots, then try the other.
# Are they both the same speed? Normally the faster DIMM will be stepped-down to the slower DIMM's speed, but rarely one of them just wont work. If it's ever going to happen I'd expect it to happen in a shuttle PC where the components are not as "capable" as a desktop.

[kimpossible]

Cheers for the reply.

The online specifications say it supports 2GB so your safe there.

# Although unlikely its worth having a poke around the BIOS settings for answers.

Everything I've read seems to point me towards the BIOS....I'm avoiding poking around there...but think I might have to!

# Could the DIMM be dead? Try using 1 DIMM and see if the PC boots, then try the other.

I've swapped them around in the slots, but not tried them individually. I'll see if it makes a difference.

# Are they both the same speed? Normally the faster DIMM will be stepped-down to the slower DIMM's speed, but rarely one of them just wont work. If it's ever going to happen I'd expect it to happen in a shuttle PC where the components are not as "capable" as a desktop.

I bought them together so guess they're the same speed!

[Stealth]

Your safe looking in the BIOS, if you have changed something accidentally it will ask you to save before exiting. If your really unsure just switch it off and try again!

[robwhizz]

Is the second slot a bit tight, ie was it difficult to lock the RAM in? It is possible to have the plastic locks hooked into the RAM, but it still be slightly unseated and therefore not work.

Download CPU-Z: http://www.cpuid.com/softwares/cpu-z.html
This gives plenty of info about the memory.

Plug in the original RAM (which I assume was factory fitted, or did you build a barebones?), run cpuz and post a screeny of the memory tab and SPD tab (which gives info about each slot).
Then install the 1GB modules and do the same.

Hopefully that will give us enough info to diagnose the problem.

[kimpossible]

Is the second slot a bit tight, ie was it difficult to lock the RAM in? It is possible to have the plastic locks hooked into the RAM, but it still be slightly unseated and therefore not work.

Download CPU-Z: http://www.cpuid.com/softwares/cpu-z.html
This gives plenty of info about the memory.

Plug in the original RAM (which I assume was factory fitted, or did you build a barebones?), run cpuz and post a screeny of the memory tab and SPD tab (which gives info about each slot).
Then install the 1GB modules and do the same.

Hopefully that will give us enough info to diagnose the problem.

thanks for the advice. I'll try what you have suggested and then report back.