Msg: "Memory runs at single channel. " What is that mean?

On computer starting, before windows loading on, the Dos window message says “Memory runs at single channel.” What is that mean?

I have 1.5 G ram but still feel the system not fast enough as expected. The main softwares on my computer are Windows XP, Office 2003, SAP R3 and Oracle 9i.

Will increase the points if answer is satisfied.

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crazijoeConnect With a Mentor Commented:
Dual channel is where the MB Chipset will address two channels of memory. I as in your situation you must be using different types or size of memory so it will configure itself fo single channel mode.
lchyiConnect With a Mentor Commented:
Perhaps your motherboard is a dual-channel one. You might have your memory modules installed in a way that only lets them operate in single channel mode. Since you have 1.5GBs of RAM I'm guessing you have a 1GB stick and a 512MB stick right? If that's the case, I think you can still run dual-channel DDR but differring capacities make it less effective. Most likely, you probably have the modules in the wrong slots. I have an IC7 motherboard and that's exactly what happened to me. I bought two sticks of matching DDR and I installed them so that there was one stick on each "pair" of slots. Therefore the motherboard ran them in single-channel mode. I moved one of the RAM sticks over to where it was supposed to be and then it booted up saying it's running "dual channel mode".
Oops, also forgot to add this:

Dual-Channel DDR is a technology that came out a few years back. Basically it allowed two sticks of RAM to operate with each other more efficiently.

And the comment on the speed issue. 1.5GB is a good amount of RAM for those applications. Perhaps your processor speed or your hard drive is your bottle neck.
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Lee W, MVPConnect With a Mentor Technology and Business Process AdvisorCommented:
Dual channel requires the memory to be identical pairs.  To have 1.5 GB of ram and have it be dual channel you'd need 2x512 MB Dimms (Same style) and 2x256 MB Dimms (same style) where same style means both have the exact same specifications (CAS, etc) AND they are BOTH single sided (chips soldered onto only one side of the dimm) or DUAL sided (chips on both sides).

What kind of hard drives do you have?  As suggested by Ichyi, your bottle neck is not RAM, but could be CPU (I doubt), and is more likely your hard drive.  If you have dual Channel capable board you probably have at least a 2GHz CPU.  If it's a celeron, then MAYBE the CPU), but in most cases, the bottleneck is hard drives.  What can you do to improve that?  Depends on how much money you want to spend.

FASTEST you'll get will be roughly 2-3x faster than your typical fast IDE hard drive - if you want to spend $3000+ on hard drive and controller upgrades and get yourself a SCSI RAID card and 3-6 15K RPM hard drives.  That's about the fastest you'll get now.  When configured in RAID 0 you'll get much better performance because you'll have n-heads reading data from the drives every time you have to retrieve information (where n is the number of hard drives you buy).

There are cheaper, not as good, but better than standard solutions.  One might be to get yourself a couple of 10K SATA hard drives and an SATA RAID controller.  Then you can do a 2 drive RAID 0 with some FAST drives and you'll see better performance.  That solution would probably run you ~$350 (all price estimates are US dollar and assume you live in the US)
Lee W, MVPTechnology and Business Process AdvisorCommented:
If you're not familiar with RAID, check this out:,,sid5_gci214332,00.html
jmw666Author Commented:
Thanks for all of you.
Practically, it is useless, unless you are some overclocker looking for 1% increase in the FPS (whizkidd's words).

It is a "better" way 2 RAM chips "Talk" to each other.

To pout it in simplest words to have Dual Channel, BUY Identical RAM CHIPS ALWAYS IN PAIRS.
If 1GB then: 512MB X 2, IF 2GB, then 1GB X 2, etc. ALL The parameters should be same to enable Dual Channel Mode.
Anyways, check if the 1.5 GB (1GB x1 & 512MB X1) has same specifications of FSB (One Maybe 333MHz, other Maybe 400MHz).

Ultimately I would recommend, go for a Single 2GB RAM (FSB: 667 / 800 MHz) Chip OR BUY 1 GB RAM extra to boost the Totakl RAM to 2GB Dual Channel.

RAM Is cheap now-a-days.
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