Memory problem

[steve_nfi]

Hi all

I have a problem with a PC. I bought some extra memory to beef up a PC but had trouble fitting it in the 2 spare slots. I swapped the new with the existing memory and they went in fine. Now the PC won't boot up, it recognises that the memory is there but it gets so far and hangs. I took those out and put the old back in but that does the same. Tried resetting the BIOS but now I can't even get into that.

Can anybody help me with this please?

[Michael]

Usually if the PC fails to boot, it means the memory isn't compatible with the motherboard or with old and new modules together.

 

With DDR and DDR2 memory, (on most boards) you can run them in pairs. Are the memory slots coloured yellow, black - yellow, black or similar? How many slots do you have and how many modules are you installing? There are some chipsets which stupidly don't allow you to populate all memory banks, so you have to ask the question why are they there in the first place!?

[steve_nfi]

There are 4 slots 2 black and to white (creamy).Originally there were 2 512mb cards in there and I wanted to add 2 1gb cards.

Making a total of 3gb. The 2 512 cards were in the black slots which all cards fit but neither go into the white ones.

I have PC Wizard 2008 on this PC which tells you that all the slots are the same and what type and amount of memory you can have. I trusted this because it got the original 2 correct.

[Michael]

It sounds to me you have one of these dual DDR and DDR2 boards, so you can populate the 2 x DDR or the 2 x DDR2 only, not both.

 

What motherboard do you have? Make and model would be handy.

[Michael]

Gibbo's right as well, because you only have two useable memory slots, you could only have 1GB, 2GB or 4GB (possibly, if your board supports that much). Of course there's no such thing as a 1.5GB single memory module.

[tmcd35]

I think Michael has the answer. But I recall something about memory having to be 1GB, 2GB, 4GB or 8GB - you see the increments? 3GB wouldn't be 'valid'.

 

This does depend alot on the motherboard/chipset used but, in general most mobo's support single sticks rather than matched pairs, and most mobo's support odd amounts of memory upto the max supported. So usually 3Gb is valid.

 

It usually more important to check memory speed, bus speed, ECC and buffering. The chips usually need to be the same in terms of ECC/buffering and need to support (although not necessarily be) the same memory speed.

 

Also, for some unfathomable reason, brand can also play a big part. Some mobos won't like a memory chip of said spec from brand y, but the same spec from brand x (not the jazz band ) will work ?!?

[PeterW]

What is the make/model of the PC? Or is there amodel number printed on the mainboard?

[steve_nfi]

The motherboard is a Foxconn 945G/P7MA.

The manual actually says -

"This motherboard includes four 240-pin slots with 1.8v for DDR2. These Slots support 256mg, 512mb and 1gb DDR2 techmologies for x8 and x16 devices and support a maximum memory bandwidth of 8.5GB/s using DDR2 533 memory. 10.tGB/s using DDR2 667 in Dual-channel interleaved mode. Yo must install at least one memory bank to ensure normal operation"

 

I installed the 533 version.(All four cards).