# How do I know what kind of RAM my computer uses
**URL:** https://boards.straightdope.com/t/how-do-i-know-what-kind-of-ram-my-computer-uses/321331
**Category:** Factual Questions
**Created:** [September 12, 2005, 9:26pm UTC](https://boards.straightdope.com/t/how-do-i-know-what-kind-of-ram-my-computer-uses/321331 "2005-09-12T21:26:12Z")
**Posts on this page:** 10
**Page:** 1
### Author:  [@Wesley\_Clark](https://boards.straightdope.com/u/Wesley_Clark)
#### Post date: [September 12, 2005, 9:26pm UTC](https://boards.straightdope.com/t/how-do-i-know-what-kind-of-ram-my-computer-uses/321331/1 "2005-09-12T21:26:12Z")
I know my computer uses DDR RAM but that is all I know. How do I find the PCC number because there are 2100, 2400, 2700, 3000, etc and I don’t know what I have or what is compatible? WHat all other info do I need aside from those two things and the MB capacity of my motherboard?
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### Author:  [@Fridgemagnet](https://boards.straightdope.com/u/Fridgemagnet)
#### Post date: [September 12, 2005, 9:34pm UTC](https://boards.straightdope.com/t/how-do-i-know-what-kind-of-ram-my-computer-uses/321331/2 "2005-09-12T21:34:09Z")
[Crucial](http://www.crucial.com/uk/promo/index.asp?prog=desktop) can scan your PC. Failing that, look it up from their manufacturers list. Or from your PC OEM.
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### Author:  [@Wesley\_Clark](https://boards.straightdope.com/u/Wesley_Clark)
#### Post date: [September 12, 2005, 9:38pm UTC](https://boards.straightdope.com/t/how-do-i-know-what-kind-of-ram-my-computer-uses/321331/3 "2005-09-12T21:38:45Z")
They recommended a 512 DDR 3200 stick. What do things like 3200 stand for and can I have a 3200 stick and a 2100 stick at the same time? WHat brands are good for RAM, is kingston any good?
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### Author:  [@Jurph](https://boards.straightdope.com/u/Jurph)
#### Post date: [September 12, 2005, 10:46pm UTC](https://boards.straightdope.com/t/how-do-i-know-what-kind-of-ram-my-computer-uses/321331/4 "2005-09-12T22:46:47Z")
> [@Wesley Clark](#):
>
> They recommended a 512 DDR 3200 stick. What do things like 3200 stand for and can I have a 3200 stick and a 2100 stick at the same time? WHat brands are good for RAM, is kingston any good?
[Wikipedia](http://en.wikipedia.org/wiki/DDR_SDRAM) explains DDR speeds as Gigabytes-per-second: 3200 would be 3.2 GB/s. It uses DDR-400 chips, and runs at 200MHz. Your machine’s system clock determines the speed of your DDR, but all DDR chips are basically the same – just guaranteed for different speed tolerances – so DDR-3200 will usually run just fine at 2100 speeds. Why not buy nothing but 3200, then? Because 3200 is more expensive! So only buy as good as you need.
If you know what motherboard you’ve got, you can find out whether it supports dissimilar RAM; it is almost certainly going to run all of your RAM chips at the same speed, however, even if that means running the 3200 at 2100. You can download a utility like [Crystal CPUID](http://crystalmark.info/software/CrystalCPUID/index-e.html) to determine how fast your system clock is, and use the Wikipedia article to figure out the speed of RAM you need based on that number. Remember to use the “system clock” number and not the “front side bus” number.
Also, can you tell us what motherboard you’re using (e.g. Gigabyte GA-7VM) – or if it’s an off-the-shelf PC, the make and model (e.g. Dell Inspiron 3750)? That would go a long way towards helping us to help you determine if you should get paired sticks of RAM and other considerations.
Kingston, Crucial, and Corsair are highly-regarded brands; I have never had a stick from any of those manufacturers fail on me. Ordering through Newegg gives you a safety net, as well.
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### Author:  [@Wesley\_Clark](https://boards.straightdope.com/u/Wesley_Clark)
#### Post date: [September 12, 2005, 11:52pm UTC](https://boards.straightdope.com/t/how-do-i-know-what-kind-of-ram-my-computer-uses/321331/5 "2005-09-12T23:52:58Z")
I have an Elite Group (ECS) K7AMA motherboard. It says it can hold 2GB RAM and that it has two slots for DDR RAM. So either a 512MB or 1024MB stick is what I’ll use as I only have 256MB right now.
Should I get rid of the 256MB stick altogether (It may only be a 2100 200mhz) and just buy a single 1024MB stick of 3200 400mhz and use that?
Can I run a test to see the PC and mhz values for my RAM or do I need to manually open the case to check.
My system clock says 133mhz, which is 266 DDR RAM. I’ll probably just buy 200mhz DDR RAM and it’ll automatically downshift to 133mhz, because I’m having trouble finding any 266 DDR RAM on ebay.
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### Author:  [@Wesley\_Clark](https://boards.straightdope.com/u/Wesley_Clark)
#### Post date: [September 12, 2005, 11:59pm UTC](https://boards.straightdope.com/t/how-do-i-know-what-kind-of-ram-my-computer-uses/321331/6 "2005-09-12T23:59:04Z")
What do you guys think about this RAM?
[http://cgi.ebay.com/Brand-New-Crucial-Micron-512mb-PC2700-DDR-333-Memory\_W0QQitemZ6799776248QQcategoryZ44938QQrdZ1QQcmdZViewItem](http://cgi.ebay.com/Brand-New-Crucial-Micron-512mb-PC2700-DDR-333-Memory_W0QQitemZ6799776248QQcategoryZ44938QQrdZ1QQcmdZViewItem)
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### Author:  [@chaoticbear](https://boards.straightdope.com/u/chaoticbear)
#### Post date: [September 13, 2005, 12:15am UTC](https://boards.straightdope.com/t/how-do-i-know-what-kind-of-ram-my-computer-uses/321331/7 "2005-09-13T00:15:45Z")
Huh. That CPUID thing revealed that my computer came overclocked. .35% overclocked (2166 to 2174).
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### Author:  [@Mangetout](https://boards.straightdope.com/u/Mangetout)
#### Post date: [September 13, 2005, 12:16am UTC](https://boards.straightdope.com/t/how-do-i-know-what-kind-of-ram-my-computer-uses/321331/8 "2005-09-13T00:16:39Z")
SiSoft Sandra is another good utility that will tell you about the memory you have installed and what your motherboard can support.
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### Author:  [@bouv](https://boards.straightdope.com/u/bouv)
#### Post date: [September 13, 2005, 4:09am UTC](https://boards.straightdope.com/t/how-do-i-know-what-kind-of-ram-my-computer-uses/321331/9 "2005-09-13T04:09:25Z")
If you’re going to get some RAM, you might as well go all out and get the 3200. It’s not really more expensive.
[Here’s some for $50.](http://www.tigerdirect.com/applications/SearchTools/item-details.asp?EdpNo=235775)
Or, [url=“[http://www.tigerdirect.com/applications/SearchTools/item-details.asp?EdpNo=586829](http://www.tigerdirect.com/applications/SearchTools/item-details.asp?EdpNo=586829)”]A cheaper brand for $40. I think it’s cheaper, I don’t recall hearing the brand Ultra before. Kingston and Atlas are two great brands. Hell, I love Atlas, because the top of the line RAM has a lifetime warrenty.
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### Author:  [@Jurph](https://boards.straightdope.com/u/Jurph)
#### Post date: [September 13, 2005, 1:10pm UTC](https://boards.straightdope.com/t/how-do-i-know-what-kind-of-ram-my-computer-uses/321331/10 "2005-09-13T13:10:39Z")
> [@chaoticdonkey](#):
>
> Huh. That CPUID thing revealed that my computer came overclocked. .35% overclocked (2166 to 2174).
Sounds like 13x166(.66…)MHz, and your clock is running a little hotter (167 or so). I wouldn’t sweat it. I run at 133x14.5 and see the same slightly-high clock speed with no ill effects.
As for **Wesley Clark** , I would never buy RAM on eBay, especially if the price was far below market value[sup]1[/sup]. If you are well familiar with eBay, and know that you can recoup your losses if the RAM is bad or mislabeled or what-have-you, then go for it. I’d sooner order [refurbished RAM](http://www.newegg.com/Product/ProductList.asp?Submit=list&SubCategory=147&type=Refurbished) from Newegg or Tiger Direct, where at least you know the returns policy is rock-solid.
If you really want to roll the dice (but possibly save a boatload of money) [here](http://froogle.google.com/froogle?q=PC2100+512MB&scoring=p) are some hits on Froogle for 512MB sticks of PC2100. Buy two or more for that first hit and the price comes down to $30/per. Pretty sweet…!
[small]1. This may be dumb behavior. A free-market economist sees a $100 bill on the street and ignores it, saying “nobody would leave a real $100 bill on the street - the first person to come across it would surely have picked it up!”