3GBs RAM in Dual Channel mode in Vista

HiDef

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Is it possible to use a configuration of 2x1gb and 2x512mb DDR-800 RAM modules to achieve 3GB RAM in dual channel mode? The motherboard I'm using is an Asus P5B deluxe, and running Windows Vista Ultimate 32bit edition.

RAM would be configured like this:

Memory slots 1 & 3 - 1GB ram sticks
Memory slots 2 & 4 - 512mb ram sticks
 

HiDef

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The current memory I've got is a G.SKILL 2GB KIT (2x1GB) F2-6400CL4D-2GBPK DDR2-800 (PC-6400) CL4-4-4-12 1.9 2.0V

I can get hold of a this: G.SKILL 1GB KIT (2X512MB) DDR2-800 (PC-6400) CL5-5-5-15 F2-6400PHU2-1GBNR

Are the different timings likely to affect performance? I don't want to overclock anything either. Thanks for any info on this
 

Mondoman

Splendid
...on a 32 bit system you have a 4GB limit which I believe includes your video card memory as well...
It doesn't directly include the video card memory; however, the video card may reserve a block of addresses for transferring data to/from the main system.
 

Mondoman

Splendid
The current memory I've got is a G.SKILL 2GB KIT (2x1GB) F2-6400CL4D-2GBPK DDR2-800 (PC-6400) CL4-4-4-12 1.9 2.0V
... I don't want to overclock anything either. ...
This memory already requires overclocking to run at DDR2-800 CL4-4-4-12, because it requires a boost above the DDR2 standard voltage (1.8V) to 1.9V or 2.0V in order to run properly at that speed/timings. Most performance RAM is sold according to such factory-sanctioned overclocking settings, so if you really don't want to OC, you'll need to stick to memory that can achieve its spec speed/timings at 1.8V.
However, the memory should have slightly slower settings programmed into its SPD that will work at 1.8V; one of these should be selected when you set the memory settings to "auto" in the BIOS.
This post should provide more info: http://forumz.tomshardware.com/hardware/modules.php?name=Forums&file=viewtopic&p=1249881#1249881
 

HiDef

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Thanks for the info, Mondoman. I have installed the latest version of CPU-Z to find out my Memory Timings and it appears that my RAM is in fact running at the slower 5-5-5-15 settings 8O



Now, I'm tempted to overclock, but as this computer doubles as a business computer with important data, I am really put off maunally adjusting anything for fear of getting errors or corruption in data.

Although it seems wasteful that I spent more on RAM that runs at slightly less speed, I am happy with it if I can get 3gb of RAM to run in dual channel mode. Because it is running at these timings, could I purchase the 2 512mb sticks mentioned earlier with the 5-5-5-15 timings, and safely run the whole setup with 3gb ram in dual channel mode?
 

HiDef

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Here are the specs:

Brand: G.Skill
Series: NR Series
Type: 240-Pin DDR2 SDRAM
Capacity: 1GB (2X512MB)
Speed: DDR2 800 (PC2 6400)
Cas Latency: 5
Voltage: 1.9V~2.0V
ECC: No
Registered/Unbuffered: Unbuffered
Heat Spreader: Aluminum Heat-Spreader
Manufacturer Warranty: Lifetime Warranty

Doesn't look hopeful; they have only mentioned 1.9v - 2.0v :(
 

Mondoman

Splendid
You're right, you may have to get more expensive stuff. Personally, I'd just go ahead and run my RAM at 1.9V or 2.0V. As "overclocking" goes in practice, that's not going to void any warranty or run any risk of damage. It's the equivalent of driving 65mph in a 60mph speed limit zone, not like the "street racing" you see with some of the setups here.
 

HiDef

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Thanks for your help Mondoman - I'm going to take my PC back to the computer store I purchased it from and discuss the issues you raised - such as the higher voltage. I'm going to see if I can purchase the G.Skill F2-6400CL4D-1GBPK (512MB x 2) kit, or get them to order it in. I'll report back if I have any further questions :D