Dual Channel Question

[PCDude18]

Hey guys i need some help on this one pls! Can i put in a Dual channel motherboard a single 1GB RAM? or do i need a pair of 512MB?

 

[Zorg]

Yes, you can use a single stick of ram, it just won't run dual channel ... obviously.

 

[PCDude18]

Thanx my friend for answering! To work as Dual channel i have to put 2 sticks on the coloured sockets?

 

[Zorg]

Right. They should be a matched set as well. If you look at newegg etc. you will see that some of the ram is sold in pairs that are closely matched so that they will work together.

 

[PCDude18]

OK buddy thank you

 

[Mandrake_]

Thanx my friend for answering! To work as Dual channel i have to put 2 sticks on the coloured sockets?

Not necessarily. On an Intel platform, anyway. Each channel needs to have the same amount of ram, but that can be any speed, any timings, any brand and the sticks of ram can be any size. All that matters is that the channels each have the same amount of memory. I have no idea if this holds true on an AMD platform.

Example: On my ASUS P5B motherboard I have 2GB ram. Channel A has 2x 512MB Corsair DDR2-667 memory while the second channel has a 1GB stick of Corsair DDR2-667 memory.

 

[Zorg]

You are right it is not required that they be matched but it is recommended.

Edit: some additional information

For the best dual-channel memory performance on motherboards with the Intel dualchannel
DDR chipsets, you must use identically paired memory modules in DIMM
sockets 0 of channel A and B. Identically paired memory modules must also be used
when populating DIMM sockets 1 of channel A and B. One can, for example, plug in
matching 256MB DIMMs in both DIMM 0 slots, and plug in matching 512MB DIMMs in
both DIMM 1 slots.
In this context, “matching” modules means:
1. Both modules are the same capacity (e.g. both are 256MB, or 512MB)
2. Both modules are the same speed (e.g. both are PC2700 or PC3200)
3. Both have the same number of chips and module sides (e.g. both have the
same number of chips on the module, and both are either single-sided or
double-sided).

Link: http://www.kingston.com/newtech/MKF_520DDRwhitepaper.pdf

The matching that I was referring to is same production run etc. to make as closely identical sticks as possible. Those are the ones sold in pairs. You can buy one 1Gig now and one later but I would at least buy the same part number stick even though they are not "matched sticks".

 

[Mondoman]

That white paper is outdated and doesn't apply to the more recent Intel chipsets, which work as M described.

PS - The white paper is dated Sept 2003.

 

[rodr]

hey all, i have another question regarding dual channel.

what would be te difference from buying for example 2 x (1Gb) in dual channel, you know.. buying them alltogether, and from buying them individually (piece by piece)

I currently have 2 x (245 mb DDR2 PC-4300. I was going to but 2 GB DDR2 PC5300 (667mhz) in dual channel; this was months ago (im curretly waiting for a video card to be released) and the RAM was at $175. Now is at $89 (wow!)

So i was wondering if my computer would be compatible with a higher RAm speed, such as 800 Mhz, which im not sure. the problem is that i have a pre-built sony vaio (I KNOW, I KNOW), what data would youy need to see if my computer can go higher than 667mhz?

Im sure i would see a big difference from 512MB to 2 GB, even at 667mhz, but im just seeing which option would give me the best deal.

thanks.

 

[Mondoman]

Your MB/computer manual (or Sony tech support) should be able to tell you the maximum memory speed supported by the MB.
However, you can always run faster-rated RAM at a slower speed without problems, so there should be no problem using RAM rated at DDR2-800.

 

[rodr]

yes but what would be the point of using 800 mhz, if the computer is actually taking a slower speed of 667mhz. in that case i could just but the ram that actually has 667 for a better price, that is im gettin the same performance.

would it be the same?

Also.. i cant find that thing on my manual, how else could i find out?

 

[0d1n]

Can you post the model number of your Vaio?

 

[Mondoman]

These days, DDR2-667 is usually not much cheaper (if any) than DDR2-800. DDR2-800 is also likely to be more useful for a future system when you upgrade.

 

[rodr]

ok so i shouyld go for 800mhz even if my computer would grab 667mhz?

this is the one i was going to buy..
http://www.newegg.com/Product/Product.aspx?Item=N82E16820134046

i found this one, which is 800mhz
http://www.newegg.com/Product/Product.aspx?Item=N82E16820145590

its pretty good WITH the rebate, and ends on 5/7/07, and i would be buying RAm after the HD2600XT is release to drop the prices (of vid cards obviously.. im gettin one too)

so without the rebate its $40 more for most Kingston or Crucial models.. and im not even sure if my computer supports 800mhz... theres also the voltajes, that last one works at 1.9 V, i think my supported voltage is around 1.8V (according to PC Wizard)

my computer model is: RB VGC-RB55MGX

 

[Mondoman]

The two RAMs you listed are in completely different categories: the Kingston is a basic "value" line, while the Corsair is a premium "performance" line.
As for voltage, any DDR2 RAM that doesn't work at 1.8V is by definition defective. You might want to read this post for some more details: http://forumz.tomshardware.com/hardware/modules.php?name=Forums&file=viewtopic&p=1249881#1249881

 

[rodr]

Well, the RAM i have is running at 1.8 V (i think), as i found this on PCWizard, on the section of Memory:

Voltage : SSTL 1.8v

I also found this under the chipset section

FSB max. Support : 1066 MHz
RAM max. Support : DDR2 (667 MHz)

Thats why i dont know if my computer can handle more than 667mhz, what do you think it means?

should i stick with PC5300 at 1.8 V?

 

[Mondoman]

I'm pretty sure that 1.8V in the "Memory" section is just listing what the module is designed for (i.e. DDR2 -> 1.8V). To look at current memory running conditions, you need to look under the "Chipset" section, IIRC.

 

[rodr]

all i have on the chipest section is the following:

General Information :
NorthBridge : Intel i945P
SouthBridge : 82801GB/GR (ICH7 Family) LPC Interface Controller

NorthBridge Information :
Architecture : Direct Media Interface (DMI)
Manufacturer : Intel (Sony Corp)
Codename : Lakeport
Revision : 00
Bus Speed : 200 MHz
FSB Frequency : 800 MHz (QDR)
FSB max. Support : 1066 MHz
RAM max. Support : DDR2 (667 MHz)

Memory Information :
Type : DDR2-SDRAM PC2-4300
Frequency : 266.7 MHz
DRAM/FSB Ratio : 4/3
Supported Channels : Dual (128-bit)
Activated Channels : Dual
ECC Diagnostic : No
CAS Latency (tCL) : 4 clocks
RAS to CAS (tRCD) : 4 clocks
RAS Precharge (tRP) : 4 clocks
Cycle Time (tRAS) : 12 clocks

it says the speed but i dont see anything about voltages. ive been told that value ram has a batter chance to be compatible with my computer, would i see a big difference from running 2 GB at 667 to 800 mhz?

 

[Mondoman]

With a pre-built computer like your Sony, there may not be an easy way to see the DIMM voltage, but since there's almost certainly no way to change it from the standard 1.8V, that's not a problem.
It's not really that "value" RAM is more likely to compatible with your computer, it's that you should buy only RAM rated at 1.8V. Pretty much all "value" RAM is rated at 1.8V, but some "premium" RAM is also rated at 1.8V.

Currently, you are running your RAM at DDR2-533 in dual-channel mode, for a 1066MHz effective data rate on the *memory bus*. Your FSB is only running at a 800MHz effective data rate, so its max throughput is already more than saturated by your current RAM speed. I wouldn't expect to see a noticeable increase in performance by boosting the RAM speed to DDR2-667 or DDR2-800 without speeding up the CPU.

 

[rodr]

wow... well ppl have told me i would see a big difference upgrading from 512 mb to 2 gb, (upgrading the speed also). If i was to upgrade my CPU, i would have to upgrade my Mobo and so on.. and even some people say that i cant just switch mobos like that.

even if i buy the ram with 667 speed by CPU would saturate it? thats just wrong..

does this mean im screwed?
:x

 

[Mondoman]

You will definitely improve Windows performance by going from 512MB to 2GB of RAM, because RAM is much faster than virtual memory (hard disk). However, individual programs aren't likely to be much faster, rather you'll be able to switch between multiple open programs with less of a delay, and so forth.
My point on the RAM speed was just that your RAM is pretty much already faster than your CPU can handle, so adding faster RAM won't be significantly different from adding RAM that's the same speed at what you have. Definitely do go to 2GB total, though.

 

[rodr]

all i can say is: thank you "pre-built..."

i seriously didnt think buying a pre-built would give me this much trouble, and i bought this thing like 4 months ago.i pretty much have to upgrade everything thats in the freaking case to get a decent performance in games/multi-tasking.

what are the chances of me buying a core 2 duo thats compatible with my mobo?


THX SONY!

 

[Mondoman]

...
i seriously didnt think buying a pre-built would give me this much trouble

The deal with pre-builts is that they should be quite hassle-free IF they do what you want without needing any upgrades.
Upgrading is the big problem, because the components typically have little capability for upgrading, as they have been designed/chosen to be as cheap as possible while *just* meeting a certain performance requirement.

...

what are the chances of me buying a core 2 duo thats compatible with my mobo?...

I would guess zero, but check with Sony. To be fair, it's really not their fault that you ended up wanting/needing a more powerful computer.

 

[rodr]

ok well... ill just stick with the 2 GB of DDR2 667mhz, and ill try to upgrade my mobo later.. theres nothing much i can do rigt now.


thanks for your comments mondoman

 

[Zorg]

I've been out of town and your probably not even still watching this thread. If you are, could you give me a link with the specifics of just exactly what kind of mixing of sticks on a bank is acceptable? I always understood that the sticks should be as close as possible to get the best performance but I haven't stayed up to date on the newest chipsets. I would like to get the latest information if there have been changes. If you don't have any links off the top of your head then I'll just Google it.

Edit: Never mind I found it. It appears that you can mix sticks but you take a performance hit. I don't really see the point.

Dual-Channel Asymmetric
This mode is entered when both memory channels are routed and populated with
different amounts (MB) of total memory. With the aid of Intel Flex Memory Technology
this configuration allows addresses to be bounced between channels in interleaved
mode until the top of the smaller channel’s memory is reached, allowing for full dual
channel performance in that range. Access to higher addresses will all be to the
channel with the larger amount of memory populated; thus giving single channel
performance through those addresses.

ftp://download.intel.com/design/chipsets/applnots/31320702.pdf