Nickcn
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Pi3 sdram freq 900MHz?

Tue Mar 22, 2016 7:53 pm

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bleep42
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Re: Pi3 sdram freq 900MHz?

Tue Mar 22, 2016 8:31 pm

It'll be 450 MHz actual clock, but it's ddr ram (double data rate) so each clock cycle is effectively doubled so giving the 900MHz figure. Completely normal. :-)
Regards Kevin.

Nickcn
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Re: Pi3 sdram freq 900MHz?

Tue Mar 22, 2016 8:42 pm

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jdb
Raspberry Pi Engineer & Forum Moderator
Raspberry Pi Engineer & Forum Moderator
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Re: Pi3 sdram freq 900MHz?

Tue Mar 22, 2016 8:55 pm

Actual clock.
Rockets are loud.
https://astro-pi.org

Nickcn
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Re: Pi3 sdram freq 900MHz?

Tue Mar 22, 2016 8:57 pm

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GTR2Fan
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Re: Pi3 sdram freq 900MHz?

Tue Mar 22, 2016 9:02 pm

I did bring this up before in the hope that it might be corrected, but the information on the Pi3B still hasn't been changed to be in line with that given for the Pi2B. I think it's a shame as some people will undoubtedly be sucked in to buying a Pi3B thinking that the RAM is twice the speed of that on the Pi2B, which it clearly isn't. :roll:
Last edited by GTR2Fan on Tue Mar 22, 2016 9:04 pm, edited 1 time in total.
Pi2B Mini-PC/Media Centre: ARM=1GHz (+3), Core=500MHz, v3d=500MHz, h264=333MHz, RAM=DDR2-1200 (+6/+4/+4+schmoo). Sandisk Ultra HC-I 32GB microSD card on '50=100' OCed slot (42MB/s read) running Raspbian/KODI16, Seagate 3.5" 1.5TB HDD mass storage.

Nickcn
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Re: Pi3 sdram freq 900MHz?

Tue Mar 22, 2016 9:04 pm

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GTR2Fan
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Re: Pi3 sdram freq 900MHz?

Tue Mar 22, 2016 9:06 pm

No. They both use the same RAM chip. It's actually rated at DDR2-800, ie, 400MHz, so it's already slightly overclocked on both at the stock clock speed of 450MHz.
Last edited by GTR2Fan on Tue Mar 22, 2016 9:08 pm, edited 1 time in total.
Pi2B Mini-PC/Media Centre: ARM=1GHz (+3), Core=500MHz, v3d=500MHz, h264=333MHz, RAM=DDR2-1200 (+6/+4/+4+schmoo). Sandisk Ultra HC-I 32GB microSD card on '50=100' OCed slot (42MB/s read) running Raspbian/KODI16, Seagate 3.5" 1.5TB HDD mass storage.

Nickcn
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Re: Pi3 sdram freq 900MHz?

Tue Mar 22, 2016 9:07 pm

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GTR2Fan
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Re: Pi3 sdram freq 900MHz?

Tue Mar 22, 2016 9:10 pm

The answer to that question is random. There is no possible way of guessing how far an individual RAM chip will go, but 600MHz (DDR2-1200) seems to be the stable limit anyone has reached so far.

On the basis that the RPF are happy to quote one measure of RAM speed for one product and a different measure of RAM speed for another product when they're actually both the same, sig appropriately updated. ;)
Pi2B Mini-PC/Media Centre: ARM=1GHz (+3), Core=500MHz, v3d=500MHz, h264=333MHz, RAM=DDR2-1200 (+6/+4/+4+schmoo). Sandisk Ultra HC-I 32GB microSD card on '50=100' OCed slot (42MB/s read) running Raspbian/KODI16, Seagate 3.5" 1.5TB HDD mass storage.

Nickcn
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Re: Pi3 sdram freq 900MHz?

Tue Mar 22, 2016 9:19 pm

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GTR2Fan
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Re: Pi3 sdram freq 900MHz?

Tue Mar 22, 2016 9:25 pm

That's a totally different thing. We're not physically swapping the RAM for something else, we're just changing the speed it clocks at. It'll go as fast as it goes.
Pi2B Mini-PC/Media Centre: ARM=1GHz (+3), Core=500MHz, v3d=500MHz, h264=333MHz, RAM=DDR2-1200 (+6/+4/+4+schmoo). Sandisk Ultra HC-I 32GB microSD card on '50=100' OCed slot (42MB/s read) running Raspbian/KODI16, Seagate 3.5" 1.5TB HDD mass storage.

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