How can you be sure of compatible RAM?

[swee'pea99]

I'm looking to buy an old PC and trying to work out before I buy how much it would cost to upgrade the RAM. I can find new sticks easily enough, but I'm not sure what search terms to use on ebay to get 'the same thing' 2nd hand and cheaper.

Would I be right in tninking that if the Crucial site says I need DDR PC2700 184-pin DIMM, any stick on ebay that meets that spec will be ok? Or are there other numbers I need to look out for? Thanks if you can help.

 

[GrasB]

You got it mostly right if in doubt use Crucial & buy from them to. Yes they are expensive but you've got their guarantee, which is very useful if you buy for a specific PC or motherboard.

There are various types of ram, you will probably want non-ECC unbuffered dimms (common as muck PC ram). Also there may be problems with chip densities with dimms that age if you have a really cheap & nasty PC.

 

[accountantpete]

Ideally you want to access the support site for the motherboard and search for the Qualified Vendors List (QVL) or some similar terminology - if it's a decent board there should be a list of compatible memory, giving names of vendors and more importantly the part no.

 

[Garz]

Find the motherboard make model version either by software (if sisoft still do it sandra or cpu-z) alternatively open the case up and locate the sticker. Once you get that we can identify the exact memory that would fit.

 

[beanzontoast]

Your motherboard manual should have the exact description of the memory it requires.

 

[swee'pea99]

Hi guys

Thanks for the responses but like I say, this is a case of trying to do my homework before I buy. So I can't open it up or look in the manual. All I have to go by is a model number on ebay, and I'm trying to find out, eg, how much I'll have to pay to up the RAM from 500 to 1 gig before I decide whether to get the PC. Because I know that a 512 stick can cost anything from a tenner to fifty squids, depending, which makes a helluva difference when you're only looking to pay thirty for the PC. You heard right: £30, give or take. I don't need anything fancy. I don't play games or record music at work; I just need to be able to run basic MS Office stuff and basic internetty stuff, and that's it. I'd just like to be able to get 1gig of RAM in there because I know it makes XP happy.

 

[accountantpete]

I'm no expert but I believe that the BIOS in the MOBO is set up to recognise only the memory sticks in the QVL - so if you get a pair that aren't on the list they will not work.

 

[swee'pea99]

'Mobo'? Ah, that must mean motherboard. 'QVL'...um, isn't that a shopping channel? (Quick google...Ah, Qualified Vendor List.) Hmmm. I'm not sure about that. I think I might just do a search on

non-ECC unbuffered DDR PC2700 184-pin DIMM

and see how it goes. I'll report back after I've screwed up again.

 

[Garz]

I'm no expert but I believe that the BIOS in the MOBO is set up to recognise only the memory sticks in the QVL - so if you get a pair that aren't on the list they will not work.

There may be a list of endorsed manufacturers however alot of the major brands all use similar chips, a bit like monitors and tellies that rebadge.

There can be certain issues with one specific brand to avoid, but over the twelve or so years I have built machines I have yet to see it. By the sounds of it, its probably a premade unit with many of the components not listed till you open the thing up.

 

[Sittingduck]

Any DDR PC2700 184-pin DIMM is compatible with a Motherboard that has DDR 184-pin DIMM slots. The PC2700 part is the speed (frequency) rating. I would say for a 2nd hand PC you will be fine to mix and match brands but 2nd hand memory might be unreliable. Impossible to tell really but the prices of new memory these days means it's probably sensible to get it new. You may find the older/slower memory is actually more expensive then the newer faster rated stuff though. Generally it's backwards compatible and faster rated dimms will run at a slower speed okay. Need to match the type though - eg. pins and DDR / DDR2 etc.

Oh, and check that if you need Non ECC memory, you don't accidently get ECC memory (parity checking stuff) and vice versa. It will highly likely be non ECC stuff for a 2nd hand PC anyway.

 

[HJ]

Use the Crucial System Scanner tool and it will tell you all you need to know...

 

[ian turner]

If you buy from a vendor who does not specify that the memory is suitable for speciifc pcs/motherboards and it doesn't work then potentially you end up buying 2 lots of RAM.
Its never a good idea to buy something like RAM off fleabay rather than a reputable dealer.
Use one of the suggested scanner tools be it sisoft, belarc or the crucial scannerthough that can sometimes give advice that contradicts the crucial selector (such as this board supports DDR2 when a search reveals that this board supports DDR2 badly sue the manufacturer) and then feed the details into the crucial selector.

 

[Over The Hill]

I am not at all teccy but if you have x ram and a spare slot then another ram that is sold as the same must work. If it has both slots filled already then it probably is not up to the Ram you want.

 

[ian turner]

Correct you are not techy as usually the slots can take 2 or 3 different sizes of RAM. The only significance of all slots being filled is that this may mean you have to buy 2 sticks of RAm to achieve your target amount (e.g my acer laptop had 1GB of RAM but due to it being 2x512MB I had to buy 2x1GB to achieve 2GB )

 

[rh100]

SP - for the cost difference - I would highly recommend 2GB instead of 1GB - makes XP run fairly well even if the other specs are a little low.

As already stated - make sure you get the right type ie DDR or DDR2 non ecc etc', but get a matched pair from someone willing to accept a return/swap and you won't go far wrong. Go with crucial rather than ebay.