# Are these RAM modules interchangeable?



## Done_Fishin (Oct 10, 2006)

I am currently using 4 pieces of (Transcend) RAM 256MB DDR DIMM 3200-400.

I have been given 2 pcs of Kingston KVR400X64C3A/512 (512MB) RAM

Am I correct in assuming that I can swap out one pair of my 256's for this new pair ? 

Will I have any problems ?
Not worried if the 512's drop down in speed but would prefer not to put in slower memory and drop my 256's speed. I have no games applications that are running except that my PC is used as a gateway for 3 other pc's to a 1024/256 KBPS DSL connection to the internet.


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## TheMatt (May 9, 2006)

Just from looking at the model number of the kingston RAM, it looks like it is DDR400. Is that correct? That is the speed of your current RAM, and they will operate at 400 MHz since they are the same speed.


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## Done_Fishin (Oct 10, 2006)

I don't know much about this pair, I was given them as used but working. I did a google search for the RAM type KVR400X64C3A and didn't come up with any satisfactory results. In my mind I was thinking I have 3200's .. 
I note that the DIMMS are doublesided and have a total of 16 chips (8 each side) but technology is changing so fast these days that it's difficult to keep up let alone research it properly without some help. I remember the days when you could swap a Flash BIOS ROM with a programmed EPROM and the PC would still work, it was only a few years ago, now that has all changed.

wrt the RAM I haven't tried swapping them yet since I am in need of having the puter open for network access by everyone else. I just wanted to be sure that I wasn't going degrade my system by doing so.

I managed to find a bit of info about the 512's that says it's 3-3-3 whilst on the packaging for the 256's it says 2.5-3-3.
Had I seen somewhere that 512's are 3200-400 I wouldn't have bothered asking anything here .. unfortunately I didn't see that info anywhere.


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## 8210GUY (Aug 29, 2006)

>>>Here<<< would appear to be your new ram, and going by that you have 512MB 400MHz DDR Non-ECC CL3 (3-3-3) DIMM ram, so as said it should work together, mind you 2 points I'll quickly make, first is run them as pairs so they aren't mis-matched, and secondly I have had boards in the past hat were extremely finicky about it's ram only accepting certain size modules, so it may be worth seeing if your motherboard manual has any mention of such a thing to save headaches further down the road, took me 3 sets of ram, an understandable\helpful shop and motherboard tech support to finally figure out the board was rejecting any configurations of ram it didn't like, from memory they had to be in multiples of 8 for it to accept them lol.


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## Done_Fishin (Oct 10, 2006)

Thanks for the help guys, I now know that I shouldn't be wasting my time trying although there are no guarantees that it will work. I'll remove all 4 banks first and justb run with the new stuff in pairde banks. When I am happy that it is running I will add back one of the other pairs and see if I am having any compatability problems.


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## Done_Fishin (Oct 10, 2006)

I got around top checking this out tonight
First I doidn't do what I said I was goinf to do , I removed a single pair of 256's in the first slots, added the 512's and was then upset when I only saw 1024 MB during POST.
I removed the second pair of 256's and replaced them with the first pair I had removed, but no change .. I though to myself that singles & doubles DON'T mix.
I removed the 256's and powered on again. This time I only saw 512MB .. suspicious ...
I tried them one at a time seeing only 512 then tried with both together again. I saw 1024 MB pop up, so thought bad contact added a pair of 256's whilst adding Mentest86 Floppy to the drive, saw 15xxMB before the floppy booted and then the failures started showing ... Shut down removed the 512's & replaced the memories as they used to be .. Memest86ed the cards to be sure all OK .. then rebooted into Windows
I reckon if I get a good pair of cards then I should be able to use the mix .. but I'll give tyhe other cards a good test before I procedd any further.
The 512's are Kingston & lifetime guarantee. Will I need to hold the proof of purchase if I want to RMA them?


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## JorisS (Jan 19, 2007)

Did you check what configs your motherboard supports?


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## 8210GUY (Aug 29, 2006)

Well as I've never dealt with them I can only guess, I would say yes, always assume they want a receipt and you'll never go wrong, but they may well take it without, I can't say personally, but I'm guessing the motherboard your trying to use them in is not the one listed in your specs ? if so let us know the model and we can try to see for you, but if it is the one in your specs it says the following, hope it helps.


> Memory Configuration
> This mainboard provides three 168 pin 3.3V PC133 un-buffered/buffered DIMM sockets to
> support a flexible memory size ranging from 8MB up to 1.5GB for SDRAM or from 8MB up to
> 768MB for EDO memory. PC66/PC100/PC133MHz SDRAM with SPD , 66MHz EDO DIMMs
> ...


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## Done_Fishin (Oct 10, 2006)

8210GUY said:


> I'm guessing the motherboard your trying to use them in is not the one listed in your specs ?


quite right , it's the system under my signature ASUS P4S800D, currently with 4 sticks of DDR 400 - 256MB one pair is jetway and the other transcend. Working ithout showing any signs of problem (touch wood)


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## Done_Fishin (Oct 10, 2006)

JorisS said:


> Did you check what configs your motherboard supports?


Front Side Bus 800 / 533 / 400 MHz 

Memory 4 x 184-pin DIMM Sockets support max. 4GB unbuffered non-ECC 
PC3200/2700/2100/1600 DDR SDRAM memory
Dual-channel memory architecture


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## JorisS (Jan 19, 2007)

I dowloaded the manual to your motherboard from Asus and looked up the info about memory (page 1-11). Here's the page, but to be honest I don't fully understand it :redface: :











There some additional info on page 1-10.


So either you run with 1 DIMM, or you use dual channel is what I make of it?

Make sure you have them in the proper slots (same colour).

Sorry, can't really make much more of it.


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## Done_Fishin (Oct 10, 2006)

JorisS said:


> I dowloaded the manual to your motherboard from Asus and looked up the info about memory (page 1-11). Here's the page, but to be honest I don't fully understand it :redface: :
> 
> 
> 
> ...


Hi Joris

Manuals are something I have been using for the last couple of decades .. I am sure it's where the RTFM phrase started .. Thanks for taking time to dig into my problem though and here is a short educational trip for you too .. you may well need it later when trying to figure out your own board problems ..

I've modified your picture to show my memory sticks highlighted with yellow and a red arrow pointing to them. The Transcend & JetRAM are more or less identical except that one set of boards have an extra Chip for parity but that hasn't been enabled in BIOS. parity checking costs time .. 










In table 1 we are shown how we can use a single stick of single channel memory. It shows that the memory stick may be inserted into any memory slot, and should be recognised. There is no requirement (as in some motherboards) to use a specific slot first.

In Table 2 we are shown where we can use "pairs" of identical RAM in order to make use of DDR technology. We should use slots which are of the same colour. It doesn't make any difference which colour we use as long as we use both at the same time. If we do this we will be able to use DDR memory in Dual Channel mode, which will effectively increase our memory access time.


When I was checking my sticks, as pairs, I was making sure that all memory was inserted as per table 2. In fact my current memory is installed as per table 2 with all 4 slots populated, ie installed, and each manufacturers pair is installed in the same colour slot.
When I checked out the memories individually I put the stick in the first BLUE slot closest the CPU or DIMM A1 (BLUE).

The Notes below table 2 tell me that I can install pairs of sticks with different sizes ie 2 * 256MB plus 2 * 512MB in DDR mode provided I keep the pairs in the same coloured slots. That is also what I had done.

Hope this helps you to understand what I have been doing and might help you also to understand what you may have to do later should you get into this state. I was justb trying to confirm that I wasn't going to get any problems by mixing, since although theory is fine, a dose of experience cannot be beaten to understand the real situation.

This is the mobo and what you might not be able to see is that the memeory slots are coloured blue, black, blue, black from the CPU.


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## JorisS (Jan 19, 2007)

Thanks for the explanation :smile: 

I guess I misinterpreted your problem/post somewhat, I thought you cannot get 2x 512Mb + 2x 256Mb to work and show as 1536 Mb. But now I'm not sure you really did try or not.

From the manual (and your explanation) it should obviously work anyways.


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## Done_Fishin (Oct 10, 2006)

My original question was whether I was able to replace 2 of my 256MB sticks with 512MB sticks and whether I was likely to have any problems. The response was more or less positive and I got some more info about the 512MB's that I was missing .. I was guessing that they were DDR400 but I wasn't sure.
I tried only to find that I had a duff stick or two of 512MB's .. which is unfortunate. Since they are labelled as "lifetime" I am assuming that I should be able to RMA them for a pair of new sticks. However I was given them and do not have the reciept. I am hoping that won't affect the guarantee.

Don't worry about misunderstanding the questions, it's easy to do! It's also easy to assume that we know whet we are asking for and that everyone else will/should understand too! :grin:
Thanks for taking the time to look and give your input. If you have also understood something new from this then the post was not wasted at all ..


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## 8210GUY (Aug 29, 2006)

Done_Fishin said:


> In Table 2 we are shown where we can use "pairs" of identical RAM in order to make use of DDR technology. We should use slots which are of the same colour. It doesn't make any difference which colour we use as long as we use both at the same time. If we do this we will be able to use DDR memory in Dual Channel mode, which will effectively increase our memory access time.


That was exactly what I was on about in an earlier reply about making sure they were paired up, logically the 512 sticks should be in the blue slots and the 256 sticks in the black so they are each paired, or possibly vice versa just to test it's not being over fussy, but it sounds like your already doing that, so if that isn't working you may be forced to choose whether to use them and leave the others out, or carry on as you were prior to this, shame it's playing you up


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## Kalim (Nov 24, 2006)

Make note that your Kingston RAM VDIMM is 2.6V.

If you try it and it works, you won't have a problem! :grin:

To know or sure before trying.. we're on fuzzy lines.


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## Done_Fishin (Oct 10, 2006)

Sorry Kalim, whilst I understand that the Kingston RAM is 2.6V, I am not sure what the rest of the message is supposed to mean .. as for fuzzy lines ?? :grin:


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## Kalim (Nov 24, 2006)

Just that before trying any specific RAM module, you can never really be sure if it will be compatible. :grin:

Is all working properly now?
If so what final setup did you manage to pull off?


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## Done_Fishin (Oct 10, 2006)

I have yet to go back in and check out the individual 512's to see if just one or both are bad. I am back at square one with my 4 sticks of 256MB until I see what else can be done. If I get the chance I will power off to check tomorrow. The curse of using the PC as a server for the rest of the network. I'm getting tired of switching around, re-routing then changing all back again only to find that something needs tweaking .. was working, now it's not stuff!


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## 8210GUY (Aug 29, 2006)

Can you not test the ram in another machine to save disruption ? at least you'd know if it was good ram or not.


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## Done_Fishin (Oct 10, 2006)

I don't have another PC to use that has DDR400 except for my son's PC .. but he's usually on it most times of the day except when his girlfriends around .. and then they are in the same room as the PC .. so it's a bit difficult. Don't want to be a fly on the wall :grin:


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## Kalim (Nov 24, 2006)

I think checking them one by one is your best bet now. :sayyes:


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## Done_Fishin (Oct 10, 2006)

That's the plan, see which is faulty then see if I can get it/them changed. The time is ripe for a shutdown anyway .. 
TTFN


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## linderman (May 20, 2005)

mixing ram brands is a hit & miss thing ~~~ even when the ram being used is on the list; the list is meant to mean they will work by that brand and model name in either a 

single stick, dual stick or 4 stick configuration then you have to read the SS (single sidded) DS (double sided) chip stuff

the QVL will even list which ram make and model will be compatible with four sticks


however; as I am sure you guys are aware, the list does not include mixing matches and getting dual channel performance

thats really squeezing the lemon

but often times it does work, but it works most *often*when when the mixed pairs are the same *spec* Cas latency, speed, DS & SS stuff etc

the more the variables on the mixed pairs the more the chance for failure / end of story

I think you will have no problem getting a replacement stick for your dead one with the lifetime warranty, send them both in though if they are a matched pair. Otherwise they may send you one back that isnt a match  

keep us posted


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## Done_Fishin (Oct 10, 2006)

Well as it happens I shut down and then tried each stick (after cleaning off the edge contacts) again but in different slots ie one was tested in slot 1 then the other in slot 3. Both passed 2 rounds of tests without a hiccup. So I then ran a copuple of rounds of tests as a pair (slot 1 + slot3). That passed the tests too. So I added one of the other PAIRS in slots 2 & 4 .. and that's when the failures staretd showing. Removed the 256's and just ran the 512's as a pair. All working OK. So I figure that my problem is not the sticks but the combination. I must have confused my testing techniques earlier. I am now running JUST the 512's on my PC and I'll see where that takes me.
Seems I just can't get my 1534MB as yet. 

Thanks to all for the help and guidance .. moral about mixing RAMS .. just cause they're compatable with your mobo doesn't mean that they're compatable with each other!


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## Kalim (Nov 24, 2006)

To me it doesn't seem like a brand incompatibility but one of mix-match sizing. If you can ever get hold of a similar make/model 512MB RAM stick then place that in slot 2 or 4 and check to verify this. If they work, its the sizing.

It is pure "speculation" if any piece of RAM will work alongside another of a different brand, size, latencies. The latter and voltage is where I've seen most incompatibilities. (even myself :sigh

Thanks for keeping us posted and you're welcome :grin: I'm actually fiddling to get working some RAM on a system myself today


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## Done_Fishin (Oct 10, 2006)

The stats ( that I haven't delved into to understand) say that the 256's are 2.5-3-3 whilst the 512's are 3-3-3.
I am still running well after leaving the 512's installed. I am wondering whether the problems are caused by a mix of single side / double side memories. Without having access though to some double sided memory of the Transcend / JetRAm style though I can't prove anything. Transcend and JetRam are to be found on the same site at transcendusa.com if anyone is wondering. 
Strange stuff memory .. never had problems mix'n'matching before I went over to DDR!


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## Kalim (Nov 24, 2006)

Done_Fishin said:


> The stats ( that I haven't delved into to understand) say that the 256's are 2.5-3-3 whilst the 512's are 3-3-3.


In the BIOS, they can sometimes be set to run at only one latency. If set by SPD they will run at separate native timings AFAIR. If you run SiSoftware Sandra or HWiNFO32 it will portray to you what they're running in at the moment. 3 clock cycle delay is obviously slower than 2.5 but I'm sure that both can run both those timings so that won't be a problem. 3 CAS is the safest config and slowest, while 2 is the quickest and least stable. 
CAS Latency aka Column Address Strobe Latency aka CL is basically the amount of time in nanoseconds (measured in clock cycles usually) between a request to read the memory, and when it is actually output. Thats the first numerical value appended infront of the latency values. 


> I am wondering whether the problems are caused by a mix of single side / double side memories. Without having access though to some double sided memory of the Transcend / JetRAm style though I can't prove anything.


If you recall back to 24th November '06, I was having the same problem and had ample RAM sticks to verify this. My mobo was not accepting double sided but low density RAM but accepted single sided of exactly the same density, brand, size and latency. It was a new one for me back then... :4-dontkno I couldn't possibly know with yours sorry.


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## Done_Fishin (Oct 10, 2006)

This is one of those times when RTFM doesn't help and only Brute Force or "suck it & see" tactics will show the answer. I am not going (at the present time at least) going to waste any more time chasing it up. It's not worth the hassle. Experience tells me that there must be a difference running single sided and double sided boards. At first I thought that the memory might have worked because I had cleaned the edge connectors. I have had that problem back in the days of 386's on VGA cards .. 
Right now I have 1024MB RAM (in 2 sticks of 512MB) up and running on my PC. I will see wheteher it stays working. My Other 4 sticks of 256MB has been relegated to my spares box awaiting employment or just as a back up in case of future problems. Should I stumble across some other double sided DDR400 memories looking for a good home, then I will take up where I am leaving off now.


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