# Questions about replacing RAM
**URL:** https://boards.straightdope.com/t/questions-about-replacing-ram/501111
**Category:** Factual Questions
**Created:** [June 26, 2009, 9:56pm UTC](https://boards.straightdope.com/t/questions-about-replacing-ram/501111 "2009-06-26T21:56:55Z")
**Posts on this page:** 5
**Page:** 1
### Author:  [@Rigamarole](https://boards.straightdope.com/u/Rigamarole)
#### Post date: [June 26, 2009, 9:56pm UTC](https://boards.straightdope.com/t/questions-about-replacing-ram/501111/1 "2009-06-26T21:56:55Z")
OK, first of all, I’m a dunce. I’ve been messing with computers since I was a kid but still have barely the most basic knowledge of their inner workings.
I ordered some RAM sticks for my Dell XPS 400. I did the research to make sure I got the right RAM for the system, which previously had 1GB, and 4 total RAM slots. I didn’t bother to actually crack open the case though and look at them, because my computer is in a corner infested with wires and it’s a big PITA to get at it, unplug everything, then replug it in.
I assumed that there was just a single 1GB stick in there and ordered 3 more 1GB sticks. :smack: Of course, there were 2 512 MB sticks, which I discovered upon going to install them, and I’m realizing now that it probably **has** to be that way (with them paired). I also understand from my research that it’s good to have matched pairs in terms of speed and brand, and that my 32-bit XP OS will only support a max of 3-3.5GB of RAM in practice. That’s OK though, I just want to get the most out of it that I can.
My motherboard looks like [this](http://www.teachnet-uk.org.uk/2006%20Projects/ICT-AssemblingPC/AssemblingPC/PCimages/023.jpg). The 512MB sticks were both located in the slots with the white hammer latches. I took out one of them and installed the 3 1GB sticks. I realized this was a mistake when my computer started beeping when I plugged it back in and it would not boot up. So I put the original 512MB stick back in the white slot, leaving 2 of the 1GB sticks in the black hammer slots. This time, the computer booted successfully and recognized the extra 2GB of RAM.
Am I to assume the slots that make a pair are the matching color slots and **not** the two slots which are grouped together in proximity to each other? Is the reason my computer would not boot because I didn’t have matching pairs when I installed the 3 1GB sticks and left one 512MB stick on its own? Should I go ahead and order one more stick of 1GB and install it as a pair with the other, so that I have 1GB sticks in all the slots? (Recognizing that with the 32-bit OS the gain might be minimal or non-existent. Right now my computer is recognizing 3GB of RAM)
Sorry for the length of the post and I greatly appreciate anyone who can answer me. The tech help I have received here has always been invaluable.
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### Author:  [@Caldazar](https://boards.straightdope.com/u/Caldazar)
#### Post date: [June 26, 2009, 10:17pm UTC](https://boards.straightdope.com/t/questions-about-replacing-ram/501111/2 "2009-06-26T22:17:16Z")
See here for the XPS 400 service manual: [Support | Dell US](http://support.dell.com/support/edocs/systems/xps400/sm/parts.htm)
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### Author:  [@Rigamarole](https://boards.straightdope.com/u/Rigamarole)
#### Post date: [June 26, 2009, 10:23pm UTC](https://boards.straightdope.com/t/questions-about-replacing-ram/501111/3 "2009-06-26T22:23:38Z")
> [@Caldazar](#):
>
> See here for the XPS 400 service manual: [Support Home | Dell US](http://support.dell.com/support/edocs/systems/xps400/sm/parts.htm)
Ah, that woulda been a good place to check. Yeah this was my culprit:
“If possible, do not pair an original memory module with a new memory module. Otherwise, your computer may not start properly.”
I guess I should go ahead and get the 4th stick.
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### Author:  [@Alex\_Dubinsky](https://boards.straightdope.com/u/Alex_Dubinsky)
#### Post date: [June 27, 2009, 6:59am UTC](https://boards.straightdope.com/t/questions-about-replacing-ram/501111/4 "2009-06-27T06:59:52Z")
> [@Rigamarole](#):
>
> I guess I should go ahead and get the 4th stick.
Why? Like you said, you can only use 3G.
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### Author:  [@Rigamarole](https://boards.straightdope.com/u/Rigamarole)
#### Post date: [June 27, 2009, 7:39am UTC](https://boards.straightdope.com/t/questions-about-replacing-ram/501111/5 "2009-06-27T07:39:22Z")
> [@Alex\_Dubinsky](#):
>
> Why? Like you said, you can only use 3G.
Well I read it can use “3-3.5 GB” so if it’s even a tiny bit better, may as well. The RAM sticks are cheap.