I have just installed Ubuntu 14.04 64-bit on my laptop and on the system monitor it only shows 7.2 GB of RAM and not 8 GB.
Why is that?
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xiaodongjie
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Dan
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3What are your PC specs? Graphics card? Notebook or Desktop PC? – Cornelius May 05 '14 at 17:22
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800 Mb reserved for your video card. – Rinzwind May 05 '14 at 17:53
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768 MB reserved for the video card, most likely. 800 MB is a weird number and the calculation is probably off a bit (or not showing enough precision in decimal places), as it should show 7.25 GB, as 0.75 GB (768 MB) would be reserved for video. – dobey May 05 '14 at 17:57
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1Also, I'm certain this is a duplicate question of "why only XX.Y GB of RAM shown" but I can't seem to find it at the moment. – dobey May 05 '14 at 17:57
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@dobey, I think you mean this one Ubunu 14.04 RAM disappearance – user.dz May 05 '14 at 20:19
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1That question is way too new to be what I was thinking of (system RAM allocated to video has been around for a very long time). 14.04 is not the first time it would have been asked. – dobey May 05 '14 at 20:46
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possible duplicate of Ubuntu 12.04: Missing RAM and Unsupported hardware driver issue – dobey May 05 '14 at 20:47
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Could you please demarcate (is that the correct word?) my answer as best answer? It seems that it is wrong... – Kai May 06 '14 at 11:20
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This is likely to be caused by different understandings of what 1GB, 1MB and what 1KB is.
1KB could mean 1024 bytes or 1000 bytes. The same is true for MB, GB, TB etc. In this case I guess that the manufacturer defined one KB as 1000 bytes (and so on), but in the System Monitor 1KB is defined as 1024 bytes.
Kai
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I just found a Wikipedia article about this (http://en.wikipedia.org/wiki/Kilobyte). If I am understanding everything (Wikipedia and You) right memory is calculated by binary values. Please feel free to correct me, I am not an expert and my knowledge is not too big in this topic... – Kai May 05 '14 at 17:58
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Memory (RAM) is always calculated as 8 bits == 1 byte. (That is octal, not binary. Everything is always binary, because a bit is binary, and everything is made up of bits.) – dobey May 05 '14 at 18:01
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That is of course like this, but after 1 byte everything is measured in KB, where 1KB could be 1024 bytes or 1000 bytes, right? – Kai May 05 '14 at 18:04
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1@dobey No. One kilobyte (kB) is always 1000 bytes (because kilo derives from the Greek word for thousand). One kibibyte(kiB) is always 1024 bytes. [According to the international standard] Unfortunately the two terms got mixed up by people who thought it convenient to misuse a well known prefix. If some application swaps these meaning then it's fault of the developer ignorance. – Bakuriu May 05 '14 at 18:04
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@Bakuriu Why are you directing that to me? I never mentioned KB or KiB in my comments. When talking about RAM though, whether you use KB or KiB, it is ALWAYS in octal. No manufacturer anywhere sells memory in 10-bit bytes designations. – dobey May 05 '14 at 18:57
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Yes, the conversion of bits to bytes is octal. But this seems unrelated to me as I am talking about Kilobytes, not Kilobits... – Kai May 05 '14 at 19:52
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Let say, its 8,000,000,000/(102410241024) shouldn't equal to 7.45!!! where 7.2??? – user.dz May 05 '14 at 20:05
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Your answer is wrong because of my first comment in reply to you. It has nothing to do with the software showing KB vs KiB (1000 vs 1024), as memory as always shown as values based on 8-bit bytes. – dobey May 05 '14 at 20:44