Why 3 memory slots?

  mec13 21:38 28 Apr 2005

my question is why does my 'Time'computer have only 3 memory slots, 2 of which have memory cards in(DDR). I thought that memory cards had to be fitted in 'pairs, as it was my intention just to add on with another 'pair'of cards, but when opening my machine there is just one slot left. Have 'Time Computers' forgot to put that extra slot into my 2yr old Athlon 2600+, Xp2 machine. Or! can I just put one card in that last slot, to up my memory spec. According to Crucial website, my memory is 184-pin DIMM banking 3(3 banks of 1) does that sound right!! You will of course notice my complete lack of computer knowledge,so expert advice is welcomed from you all with thanks.

  Binary Ghost (the only Paul) 21:42 28 Apr 2005

from my experience u dont need to add them as pairs,in fact ov never heard of that. just make sure the mother board can cope with the amount of memory u add

  Mr Mistoffelees 21:50 28 Apr 2005

The old SIMMs had to be fitted in pairs as does RAMBUS memory. DIMMS, including DDR do not need to be fitted in pairs and as you will need to use DDR333, not DDR400, ram you should have no problem fitting 1 extra dimm.

  Mr Mistoffelees 21:51 28 Apr 2005

In my experience, and that of others, Crucial are always right.

  Joe R 21:51 28 Apr 2005


I think you are referring to dual channel memory, which are installed in banks of two, which reads both memory sticks at the same time. (rather like a hard/drive set-up in raid0).

The mobo you have will accept one, two or three modules, but read only one at a time.

Hope this helps. Joe.

  interzone55 21:52 28 Apr 2005

Old SIMMs (ie pre pentium II days) had to be installed in pairs, as do RAMBUS RIMMS.
Standard SDRAM and DDR ram can be fitted in singles.

Dual Channel DDR memory is best installed in pairs, but if a motherboard accepted this type of memory then it would have an even number of slots.

As you have a 2 year old time PC, chances are you have a very cheap MS-6777 motherboard, which whilst being highly colourful with its red and green slots, does not need dual channel memory.

  goonerbill © ® 22:44 28 Apr 2005

memory use to have to be installed with matching pairs of memory sticks when pentium 1's came out. modern pc's will accept ram added one stick at a time sdram and ddr, rambus in pairs. dual memory (to contradict alan14) mobo's usually have 3 slots for memory and slots 1 and 3 must have matching pairs to use that option and slot 2 have any size memory stick.

check your manual for the mobo, as if i remember rightly, some of the mobo's from that time could have a max of 1gb memory only and won't run with more installed.

  Totally-braindead 23:07 28 Apr 2005

I would go with what Crucial says as Mr Mistoffelees has said, as the others have said some memories did require to be put in pairs, if Crucial says your motherboard doesn't take it in pairs then I would suggest thats right.

  Mr Mistoffelees 17:52 29 Apr 2005

Further to the above, dual channel support is provided by the motherboard and not by the ram itself.

  mec13 19:15 29 Apr 2005

I'm not doubting what crucial says, it did recomend a '512mb ddr pc2700' memory card, for my machine, but because of my lack of computer knowledge, just wondered if that meant just one card, or remove my original 2 cards, and put two recomended cards in their place. My experience with computers goes back to pentium 1 days, before this machine I have now. Thats when 2 cards had to be fitted 'In pairs', but going by what you all have said, 'Things have changed' So I presume the answer is leave my original cards in thier slots, purchase just one card, which Crucial have recomended, and fit it into that third slot, yes!!. It's a good job someone knows what there're on about, I'm just trying to impress my son who thinks he know's more than me. What does a 14yr old boy know about computers than an old hand like me, bah! Thanks anyway.

  Joe R 19:24 29 Apr 2005


What amount of memory do you have at the moment, and is pc2100, or pc2700.

If it is pc2100, and the modules are smaller than the one you are about to purchase, then install your new module in slot 1.

If the ram you have is pc2100, then you would be as well buying the same type, as the pc2700 would only run at the speed of your original ram.

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