MEMORY UPGRADE - COMPATIBILITY QUESTION

[leousb]

Greetings,

Current system:
A64 3500+
MSI K8N NEO2 Platinum
1gb (2x512) - Corsair Value select Part. #: VS1GBKIT400
according to specs this memory has CAS Latency = 2.5

Questions:
1) How can I know if my current memory is working in dual channel mode??
2) I plan to buy a 2gb kit, corsair value select as well, p/n: VS2GBKIT400C3, wich has a CAS lat = 3, for a total of 3 gb of RAM, with all 4 memory slots occupied, SO is this configuration possible?? and if it is, will it work in dual channel mode?? and what CAS latency will the whole memory work at?? BTW, will this be overkill??, I just wanna be ready for future, as I basically do some "office" work , but certainly do some heavy gaming, but would like to be prepared for Vista next year, and don´t know if 1gb for a total of 2 gb would do the job.

All help from the knowleadgeable would be greatly appreciated as I plan to buy it and ship it overnight, so I can get it before Xmas.

 

[cpacini]

1) On boot up it should say id you are in Dual Channel or not. Alternativly, you can download CPU-Z(google it) and that will tell you.
2) you can run 4 sticks like that. Each will opperate at CAS 3. You will have to use a 2t command rate if you use 4 sticks, and depending on what core CPU you may have to run the memory at DDR333.

3GB is overkill, your not going to need that much for a while.

Edit: Dual Channel will work with 4 sticks.

 

[leousb]

Thx for your input cpacini, although, could you elaborate a bit more on the command rate (2t . .) or point to a link for that matter, and how would I know if my CPU would make me run the memory at DDR333?? because I actually don´t know if my current memory is running at DDR400, guess it should?? I also guess in the BIOS but not quite sure, hope you can help me out further . . .

Thx again.

 

[cpacini]

It depends on which cpu core you have, if it is a newcastle or winchester, it will have to run at DDR333. If it is one of the newer venice core chips, you should be able to run at DDR400 with all 4 DIMMs populated. Download CPU-Z, it will tell you which core your CPU is and what speed you memory is running at currently. Either way you will have to use a 2t command rate. Overall, the performance loss from 1t-2t is not that big. Do a search of the CPU forums here, the 1t/2t issue has been debated quite a bit.

If I was in your situation, I would get a 2x1GB kit and install it by itself. 2GB is more than enough, there isnt any reason to slow your system down by instaling more memory than you will ever use. Just sell the other sticks or put them in a drawer or something, if you actually need more than 2 GB in a couple of years put them back in then.

 

[Somniferum]

Originally posted by: cpacini

Edit: Dual Channel will work with 4 sticks.

He will not be able to run in dual-channel mode with the setup as described. Dual-channel with 4 sticks is possible, but all 4 sticks must be the same size and type. He is talking about running 2x512 sticks + 2x1024 sticks. That will work in single channel (CAS 3, 2T) but not dual-channel.

He could buy another 2x512 kit and run 2Gb in dual channel with 4 sticks, but as you suggested he would be better off just buying the 2x1024 kit and installing it by itself. Fewer sticks = lower latency.

2Gb is overkill IMO, and 3Gb is just silly.

 

[cpacini]

Originally posted by: Somniferum

Originally posted by: cpacini

Edit: Dual Channel will work with 4 sticks.

He will not be able to run in dual-channel mode with the setup as described. Dual-channel with 4 sticks is possible, but all 4 sticks must be the same size and type. He is talking about running 2x512 sticks + 2x1024 sticks. That will work in single channel (CAS 3, 2T) but not dual-channel.

He could buy another 2x512 kit and run 2Gb in dual channel with 4 sticks, but as you suggested he would be better off just buying the 2x1024 kit and installing it by itself. Fewer sticks = lower latency.

2Gb is overkill IMO, and 3Gb is just silly.

No, he could run with that setup in dual channel. 1 512 and 1 1gb in channel A, the other two sticks in channel B.

 

[Somniferum]

Originally posted by: cpacini

No, he could run with that setup in dual channel. 1 512 and 1 1gb in channel A, the other two sticks in channel B.

I have never heard of a motherboard that supported dual channel with 4 DIMMS that are not all the same size. I'm not saying it's impossible, but I would like to see some evidence. Do you have a link?

My motherboard manual, for example, explicitly states that "This motherboard also allows you to install four DDR DIMMs for dual channel configuration, and please install identical DDR DIMMs in all four slots." (Emphasis in the original.)

I downloaded the OP's MSI K8N NEO2 motherboard manual to check, and it's kind of vague on this point: "Users may install memory modules of different type and density on different-channel DDR DIMMs. However, the same type and density memory modules are necessary while using dual-channel DDR, or instability may happen." (Emphasis in the original.)

 

[Somniferum]

Actually I stand corrected ... I have 2-256Mb modules lying around so I figured what the hell ... popped them in with my 2-512Mb DIMMs and what do you know -- I'm now running 1.5Gb in dual-channel! Contrary to what my mobo manual says is possible ... that's crazy.

I had to change from CAS2.5 to CAS3 to get it stable in Windows, but it works! Gonna run Memtest86 overnight to make sure it's stable.

You learn something new every day!

 

[leousb]

Thanks all for your valuable input, interesting debate.

One important thing to notice, is that 2gb, in my opinion may be overkill now but it won´t in probably less than a year, with upcoming games and Vista, wich probably requires "at least" 1gb of RAM, hence 1,5 or 2 Gb would be a neccesity cause we all know one should stay away of any "min requirements" if possible, specially when Microsoft is involved. 3gb?? well, that may be overkill, and that´s why I was looking for guidance.

I´m at work now, but I´ll check what core I have, probably one of the older ones, so here is another question:

- If I have an older core A64, wich is supposed to run memory at ddr333 if more sticks are used, How noticeable will be the performance hit in real world enviroment between 1gb@ddr400 and 2gb@ddr333??

Thx again. Hope you´re around to answer, any comments welcome!

 

[uhaulball]

im a complete beginner, so if possible, be void of techno jargon.

what specifically is cas latency and timing. i always thought lower cas latency and timings are better. ie: cas lat 3 is better than 2, and timing 2-3-3-6 is better than 3-3-2-8.
i have money to spend but no clue as to what im doing with it