# pc2400 pc2100, what is the difference?

**URL:** https://boards.straightdope.com/t/pc2400-pc2100-what-is-the-difference/78880
**Category:** Factual Questions
**Created:** [August 30, 2001, 4:04am UTC](https://boards.straightdope.com/t/pc2400-pc2100-what-is-the-difference/78880 "2001-08-30T04:04:30Z")
**Posts on this page:** 3
**Page:** 1

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### Author: ![Muad\_Dib](https://avatars.discourse-cdn.com/v4/letter/m/35a633/32.png) [@Muad\_Dib](https://boards.straightdope.com/u/Muad_Dib)
#### Post date: [August 30, 2001, 4:04am UTC](https://boards.straightdope.com/t/pc2400-pc2100-what-is-the-difference/78880/1 "2001-08-30T04:04:30Z")

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What is the difference between these two RAM types?

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### Author: ![BarBQSauce](https://avatars.discourse-cdn.com/v4/letter/b/919ad9/32.png) [@BarBQSauce](https://boards.straightdope.com/u/BarBQSauce)
#### Post date: [August 30, 2001, 4:11am UTC](https://boards.straightdope.com/t/pc2400-pc2100-what-is-the-difference/78880/2 "2001-08-30T04:11:58Z")

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I believe that Pc2100 is 200mhz, or ddr of pc100 and pc 2400 is 266mhz, ddr of pc133.

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### Author: ![dorkbro](https://avatars.discourse-cdn.com/v4/letter/d/ed8c4c/32.png) [@dorkbro](https://boards.straightdope.com/u/dorkbro)
#### Post date: [August 30, 2001, 5:07am UTC](https://boards.straightdope.com/t/pc2400-pc2100-what-is-the-difference/78880/3 "2001-08-30T05:07:11Z")

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**BarBQ** is close. PC2100 DDR is the official specification for DDR memory that runs on a 133 MHz front side bus (which would be, for any DDR application, doubled to 266 MHz). PC2400 DDR is an unofficial standard claimed by a few manufacturers for the overclocked speeds at which their memory can run - and I would be associated with a 150 MHz front side bus. IIRC - the 2100 or 2400 is a measure of bits per second. The standard bus passes one byte - or 8 bits - per clock cycle, so if you multiply 8 by the bus speed (133 or 150) by 2 (because it is doubled), you get numbers close to these - (8_133_2 is 2132, but the norm for these is to round to even hundreds - I am not sure why).

Memory rated at above spec speeds might be able to be tweaked to run a bit faster even if you are not overclocking, but the biggest reason for looking at PC2400 is if you plan on seeing just how fast you can make your system run.

Hope that helps.