RAM Voltage compatibility in Motherboards

[inhuman]

I'm using an Intel d865GLC (478 pin P4, AGP; yes, that old). When I first bought RAM for this motherboard, I specifically looked to see it was 2.5V due to the exclamation in the manual: "2.5V only", and bought a DDR333 Kingston. A few months ago, I grabbed another stick of RAM (same brand, same size; Kingston, 512, DDR 400) from an acquintance of mine trashing his old system. I knew the new DDR400 stick would run at DDR333 due to the other stick, but it never occured to me to check the new stick's voltage usage, up until last week. I found out that despite it's the same size and speed, it's a different model, one that's a 2.6V stick. However, from the day I installed it in my system, I never had a problem. System recognizes the ram fine and there is a significant performance change. What could this mean? Do you think it's ok to keep using it?

Here comes the real question: I've been intending to replace the one DDR333 get more DDR400 RAM (mobo supports up to 4GB and up to DDR400 in any combination) but it's almost impossible to find 2.5V DDR400 Kingston sticks for decent prices, but both e-bay and a native site similar to e-bay is crawling with 1.6V DDR400 sticks. Do you think installing more 2.6V RAM sticks might damage the mobo? I haven't contacted Intel to ask just yet.

edit: The RAM stick I've originally bought is KVR333X64C25/512 and the one I installed a few months ago that's 1.6V is KVR400X64C3A/512; just in case it bears some explanation to the above situation.

edit: Corrected the voltage references to 2.x range (from 1.x range).

 

[inhuman]

Interesting that noone has been able (or willing) to share thoughts about this.

 

[TheBeagle]

Good Sunday Morning Mr. Inhuman.

That's an interesting question that you posed. As a general rule, there's usually somewhere between 10-20% overvoltage cushion in most memory sticks. However, it may be slightly less in older models.

However, since you already have no problems using one stick of the 400 speed stuff at the board's default voltage (1.5?), then it ought to accept another one as well. You didn't indicate whether or not you board has any BIOS settings to adjust the Memory voltages. If so, then that usually indicates the range of voltage that it will accept and function. If the board BIOS can be set to 1.6, and you get another stick of 400 speed memory, then IF you encounter memory errors, bump up the memory voltage in the smallest increments that are available, reboot, see how it behaves, and then adjust it again if you have to. Hope that helps. TheBeagle

 

[Zap]

I always thought the base voltage for DDR was 2.5v, not 1.5v. 1.5v was for AGP 8x. If you want to be absolutely positive that the RAM you buy works in that board, then buy from a vendor that guarantees it. I know Crucial does, if you use their online locator. Kingston probably has something like that at their site too.

 

[TheBeagle]

Hello Again Mr. Inhuman.

Mr. Zap is absolutely correct. If you check the info on the links that you provided in your original post, you will see that the memory voltage is 2.5 and 2.6, respectively. However, the rest of my original response is still applicable. I also believe that his suggestion about using an online memory configuration is likewise sound advice.

However, you might want to look at the differences in the memory TIMING!!! The DDR400 stuff is quite a bit faster than the 333 stick. Therefore, to get the best result, you really ought to go to the higher speed (assuming the board is built for it - and the memory manufacturer will guarantee compatibility!), since mixing the sticks is likely dragging down the faster stick to the slower stick's speeds. Enjoy. TheBeagle

 

[tcsenter]

This board is 2.6V DIMM tolerant according to the Intel Specification Update. In addition, there may be an option for DIMM voltage adjustment in the BIOS to increase the voltage.

512MB PC3200 2.5V modules:

http://www.newegg.com/Product/Product.aspx?Item=N82E16820141164

http://www.newegg.com/Product/Product.aspx?Item=N82E16820340006


1024 (512MB x 2) PC3200 2.5V module kits:

http://www.newegg.com/Product/Product.aspx?Item=N82E16820141212

http://www.newegg.com/Product/Product.aspx?Item=N82E16820211141

 

[inhuman]

Yes, those 1.5 and 1.6V references should really be 2.5 and 2.6; I was probably tired while writing the OP so I didn't notice my own fault.

Thanks for the reminder on BIOS voltage settings TheBeagle, I usually completely forget about BIOS settings. Yes, the board supports up to DDR400 and I'm forced to DDR333 due to the original stick, that's why I'm trying to replace it. I checked with Crucial and interestingly, it lists even 2.8V sticks for my motherboard, so I'm on safe grounds I guess, I'm still waiting for a reply from Intel to make sure.

edit: I just looked back at the manual and here is the exact related phrase:

"2.5 V (only) 184-pin DDR SDRAM DIMMS with gold-plated contacts"

Could the word "only" in brackets be addresset at the 184-pins instead of voltage by any chance?

 

[tcsenter]

Originally posted by: tcsenter
This board is 2.6V DIMM tolerant according to the Intel Specification Update.

 

[inhuman]

"This board is 2.6V DIMM tolerant according to the Intel Specification Update." Where did you see that, I looked for it but couldn't find?

 

[tcsenter]

Originally posted by: inhuman
"This board is 2.6V DIMM tolerant according to the Intel Specification Update." Where did you see that, I looked for it but couldn't find?

"...Intel Specification Update"