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Why does the system report 7.7Gb of total Ram when I installed 8Gb? I'm using 14.04 on a Dell Vostro 2011

Todd
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The BIOS will reserve some memory, as will the most primitive level of the kernel, including some for video, perhaps. What is reported to you via system-info (which I don't use) or free -m is what is left.
If you observe the entries in the /var/log/kern.log file from during boot, you will see many having to do with reserving memory and such, and finally, a summary line:

May  3 14:27:20 s15 kernel: [    0.000000] Memory: 15975452K/16472972K available (8029K kernel code, 1240K rwdata, 3736K rodata, 1424K init, 1292K bss, 497520K reserved, 0K cma-reserved)
Doug Smythies
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My system claimed to have 8 GB (gigabyte) of RAM. Ubuntu says it has 7.7 GiB (gibibyte).

7.7 GiB (gibibyte) = 8.26781 GB (gigabyte)

8 Gb (gigabit) = 1 GB (gigabyte)

autisumm
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    Disks are marketed this way, but RAM is always manufactured in power-of-two sizes. An "8GB" stick of RAM is always 8GiB. – Tullo_x86 Feb 21 '18 at 04:15
  • Interesting - so 1GB RAM is really 1GiB RAM. While 1GB disk is 1GB disk. Also Windows seems to get it wrong, it reports GB when really its showing GiB - my 1TB disk show as 931GB in Windows but as 1TB is Linux. – wilmol Oct 04 '21 at 04:01
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Because that's the actual size of your RAM. They say it's 8GB because it's easier to market.

Thiago Zanetti
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  • Well It was 2 4Gb modules so each one is 3.85? That is odd. – Todd May 08 '15 at 21:28
  • @Todd memory is always a power of 2^x. 8GB is what we humans understand , but 2^32 is 4GB (rounded up). Now like Dough mentioned , there's always some memory reserved by the system. Mine is one 4gb stick and 2gb stick, but reported by free -h is 5.6 gb. Has nothing really to do with marketing, just human understanding – Sergiy Kolodyazhnyy May 08 '15 at 21:50
  • @Serg Ok great info, I did not know that – Todd May 08 '15 at 21:52
  • Human understanding = easier to market (and profit). :) – Thiago Zanetti May 08 '15 at 21:53
  • Ok it just seemed an anomaly, not like this is a life or death situ...tx all – Todd May 09 '15 at 02:49
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    -1 That's just plain wrong for DRAM (primary storage). Read the other answer for the correct explanation. Your explanation may work for hard disks and other secondary or tertiary storage, which is marketed with size in gigabytes, while many programs display size in gibibytes, even if they don't say so (though 8 GB ≃ 7.45 GiB). – David Foerster May 09 '15 at 08:49