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Few questions reguarding pairing memory modules

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June 28, 2006 4:39:50 AM

Ok Im researching RAM, technologys and types as part of my A+ Training, I have a few questions.

1) Ok so I know based on bus width, and bandwidth of module, most SIMMS are installed in pairs and most DIMMS are installed indivedualy except for dual channel, RIMMS on the otherhad have a 16bit data bandwidth? but modern systems have a 64bit data bus, so do I install in 4's? pairs or indevidualy?

2) SIMMS seem confuseing also, so the first sims had 30 pins and were 8 bits wide where newer SIMMS had 72 pins and 32bits wide, so on 8 bit systems, we install individual, and on 16 bit systems, pairs, and 32bit systems in 4's?

4) On 32 bit systems 72 pin SIMMS installed individualy, while on 64bit systems pentiums we installed in pairs?

5) And for DIMMS, weather it be SDRAM or DDR SDRAM they are 64 bits wide and we install individual, unless there is dual channel?

6) My current system has both DDR and DDR2 support, I currently have 1 512MB DDR 400 module installed, is it worth the extra money to go DDR2, or is the increase in preformance insignificant?

More about : questions reguarding pairing memory modules

June 28, 2006 5:38:09 AM

are you sure it's compatible with both, I always thought DDR and DDR2 used different pin arrangements - I'm not sure tho

just make sure you're sure that they're compatible

Im not sure about the performance increase with the switch - DDR2 has higher latency but larger bandwidth, while DDR has lower latencies but less bandwidth - again, I'm not sure

Hope This Helps
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June 28, 2006 5:35:08 PM

Yes, my motherboard Asus P5VDC-MX accepts both DDR and DDR2 modules. Two slots are yellow and two slots are blue.

slavetrader: Im not sure what was funny about my post, please try to respond with relevant posts.

The purpose of my question is to gain some insight into when and when not to pair RAM modules i.e. 2 256MB modules. My confusion is mainly with Rambus and the very old SIMM modules. How do I know what the width of a data bus is on a system if I dont have any manuals?
June 28, 2006 6:31:27 PM

Rambus eh? I have two p4 systems running with rambus, so I may be able to help you.

Rambus memory has to have all the slots filled, with either RIMM or C-RIMM(Continuity RIMM)

so if you have 2 RIMM modules then you need 2 C-RIMM modules to fill the other memory slots. Basically any Combo of RIMM's and C-RIMM's can be combined to fill the memory slots

The maximum size that I've seen is 512MB per RIMM. The most popular is 256MB modules.

C-RIMMs have no size

as for older SIMMs Im pretty sure that they can be installed individually

Hope This Helps
June 28, 2006 7:13:22 PM

Thanks, so just to clerify, If I encounter a Rambus system I could install one 512MB module of Rambus, and then 3 C-RIMMs and it should work fine?

Ok so when we say old SIMMS we refer to 30 pin 8bit modules, that we install individual because those systems are 8bit systems, could I encounter a system using old 30 pin modules that has a 16bit or even 32bit bus?
June 28, 2006 8:15:45 PM

for the first part, yes but from my experience having 4 x 128MB will run faster than 1 x 512MB,

for the second part, I believe that the 30 pin SIMMs had only an 8bit bus.

Hope This helps
June 28, 2006 9:10:25 PM

1) I don't know about RIMMS.

2) That sounds right. Even more fun? Before SIMMs, you had to put individual DIP chips into sockets - 18 onto this one 386 board I had. And that only gave it 2 meg of RAM (using dense chips - could have gone as low as 512k), and it had room for 72 with a daughtercard.

3) There is no 3. :wink:

4) Yep.

5) Even with dual channel you can install singly - it just won't enable dual channel. (I'm guessing for your test, you are correct.)

6) I'm pretty sure (but check your manual) you can't put both DDR and DDR2 on those mobos at the same time - either all DDR or all DDR2. If your mobo is capable of running DDR2 at 266/533 or more, the performance is a little better. I personally doubt it's enough better - that depends on your budget and how much 'better' you expect it to be.

Mike.
June 29, 2006 3:12:47 AM

Thanks, that about covers all my questions. Indeed, I have checked and I install either DDR or DDR2 but not both at same time.

Ok so that info on dual channel, is very helpfull to know. I have added it to my notes.

Also thanks to Nitro350Z for all your help as well, when I was buying parts, I actualy contemplated, 2 x 256MB modules instead of 1 x 512MB, perhaps this might have given me faster preformance.

P.S. Thanks for spotting the missing 3, It never ocured to me.
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