Why don't I have 2048Mb of physical memory?

Sorry if this is a stupid question or has been answered a million times already:

I just upgraded my latop with 2x1Gb of RAM.
Why in Windows Vista does "System Information" tell me that Total Physical Memory is 2037.69 MB? Why isn't it 2048 MB?
Thanks in advance!

 

2048 is a rounded number.

 

What do you mean? I see that 2048 is a round number (in binary), and so is 1024, 512, 256, etc, but isn't that precisely why the chips come in these sizes? 2x1024=2048! What happened to the missing 10MB or so in my laptop?!

 

The 1024, 512, and other numbers you see out there are actually just for marketing purposes. It's actually a little bit less. If you have a 160 GB HDD, then the physical amount of space on that is actually ~149 GB. It's really a matter of marketing.
You're system is doing perfectly fine with your new stick of GB RAM.

 

you're a little confused. the difference you are talking about is 1000 MB = 1GB versus 1024 MB = 1GB when speaking of HDs. this is different.

i wouldn't worry about a missing 10 MB, who knows why it reports that way.

if you're really worried about it, check your BIOS and see what it says... or download a bunch of free utilities to see what they say.

 

Could be a number of things.

Do you have integrated or discrete video?

If it's integrated, that will be part of it (shared memory)--plus, even integrated video requires memory mapping in system ram.

Windows reports you memory that way because various devices your laptop require memory-mapped access (also known as memory-mapped I/O.)

Let's say you have a video card that has 256 MB of onboard memory, that memory must be mapped within your system memory which reduces what is available to the operating system. Or, as said earlier, your integrated video memory is being mapped. Other devices require mapping, too. For example, I think you CPU requires it's memory (4mb on the better duo core cpu).

So, since you just strolled in and gave almost no info beyond how many sticks of ram you have (laptop model would have been a good start), it is difficult to say exactly where all that memory is going

It is normal what you are experiencing, tho

 

I should probably add this mapping stuff applies to 32-bit OS...I don't think it applies to 64-bit Vista

 

Well! is that so?
I use 32 bit Vista with 2 x 1GB Crucial and Vista shows it as 2046 MB...
and btw, i have a ATI Radeon Mobility X1400 256 MB Video Card with 128 MB dedicated....

 

It's not rounding or any of that 1000bytes = 1Gig crap. RAM doesn't do that crap.

It's your graphics card taking some RAM. Most of the time those Gfx cards that share system RAM will take a few megs either to shadow the Video BIOS or another reason.

 

First, as a few others have said, no rounding takes place, and when you buy a 1024MB RAM stick, there are exactly 1024MB on it. Not 1000. You do have exactly 2048GB of RAM.

Now, I agree it's most likely that your GPU uses shared memory, so it takes a bit of system memory. Or perhaps some other piece of hardware does the same.

Technically it does apply to 64-bit as well. The difference is that memory-mapping requires free address ranges, not memory. The memory controller is simply configured so that all requests to addresses between X and Y, are sent to the hardware in question instead of to RAM. So there doesn't actually have to be any RAM at addresses X-Y. If you have 2GB of RAM, the GPU or other hardware can be mapped to the 2-3GB range, and you won't lose any RAM.
If you have 4GB RAM on a 32-bit system, there are no unused addresses, so it has to use addresses that *do* point to RAM, making that RAM unavailable and "invisible".

On a 64-bit system, you have terabytes worth of addresses, so no matter how much RAM you have, there are plenty of leftover addresses that can be used to point to hardware instead. So the mapping is still performed, it just doesn't overlap with the physical RAM.

 

And thast is where the 2mb is going--mapping the memory for your videocard and maybe cpu

It is not a 1-1 ratio (1mb of video memory to 1mb of mapping)

He likely has shared video taking up the rest

 

well, my point is that it doesn't depend on whether you are using a 32-bit OS or a 64-bit OS in contrast with what you have claimed....

I'm not bothered about the missing 2 MB

 

Wrong.

They advertise hard drives in DECIMAL while windows reports hard drive space in BINARY. This why SOOOOO many people are confused when there sould not be any confusion at all. Its LAUGHABLE how people make up theories like "After you format you lose space" or "Windows reserves space for boot info" SIMPLE LAUGHABLE!

Truth is VERY Simple people. When you buy a 160gb hard drive Windows reports 149gb. There is NO missing space since 149gb BINARY gbs holds exactly 160 billion PHYSICAL spaces for a byte. When will people learn there is NO missing space??

Just like the YEN is worth 1.5 times the dollar. Windows can tell me I have 10 yens. To me that means I have 15 physical dollars. Im NOT missing any money....

 

My system tells me I have 2048mb of RAM.

 

There's a great quantity of bad guesses in this thread. Let me try to help clear things up.

The BIOS on your machine is in ROM.

At boot, it figures out how much physical memory you have. That's 2048 megabytes.

It then takes some memory for itself. It copies its own code into that memory because RAM is substantially faster than ROM, so this helps performance.

It subtracts the size of the BIOS from the available physical memory, and reports that altered amount.

2046 megs physical + 2 megs for the BIOS = 2048 megs physical.

The BIOS might be mapping other things, but why would it take away from your physical memory, when you have a 4 gig address space, and only 2 gigs of physical memory? There's another 2 gigs of space where it could map I/O devices and not take away from addressable physical memory. Guesses about video memory and other I/O mapped memory just don't make sense. (Unless, I guess, you have some super-broken hardware that only maps to the lower 2 gigs.)

 

This really needed to be dug up! Not real productive the 1st time, let's give it a 2nd run! Until you look at what the BIOS reports or run something like CPU-Z what is the point? I think Jalf explained well. If the BIOS or CPU-Z reports 2048 you have no problem with your RAM, end of original question.

My opinion is GPU is sharing, the mapping is doubtful unless as stated you have some real messed up HW. Until OP does a little work on their own comments are useless. I say nothing is wrong! Test it!

 

Mine lists 1023mb hehe

 

If you really want to know the details, go to the Device Manager -> View Menu -> Resources by Connection -> Memory. You will see the gory details of your computer memory mapping. Down to the single byte.

The memory mapping will be shown in hex number. 2GB in decimal = 8,000,000 in Hex. So, look for memory mapping at 8,000,000 or lower, add all the reserved memory address. Subtract them from 8,000,000 hex. Convert the result to decimal. The number will be the pure memory address available for your OS.

Happy counting and if you like, tell us what you get

 

And once again not really on topic to OP's question in any relevent way. But good to know, I guess?

 

mine is only 1662, 384 goes to the video card

 

lokster exactly! If you look in Windows, if you check BIOS or use CPU-Z or use SiSoft it will tell you what you have, not just available. If I were a MOD I would close this thread. It is much nicer the 2nd time but getting nowhere. Happy New Year all!

 

What about the other two?

 

This is wrong. 64 bit Vista also maps "stuff".

 

This is why Microsoft is gonna change the memory amount display to show your TOTAL memory and not just what's available.

 

Some memory is also reserved for system processes, the kernel, etc.
For example, I have 2GB in my laptop and the following line from /var/log/dmesg lists:
Memory: 2057764k/2095688k available (2783k kernel code, 37384k reserved, 1435k data, 220k init)

 

see what you started?!

holy smokes, your computer is normal....
Like if my cholesterol is 175 and yours is 178, it's the same#....we're ok.

 

LOL yeah GEEEZ, it's the same damn number!!! You have 2 gigs of RAM don't worry!

 

I Wish I had that much RAM

 

oops

(10 chars)

 

LOL. I thought I was a stud with 4096 MB

 

This is in regards to the gateway t-1616. I put 2x2gigs making a total of 4 gigs, but it states only 2430 mb of ram?? Is this the maximum or does it not state the right number??

these are the specs http://assets.gateway.com/s/Mobile/2007/Triton/1014772R/1014772Rsp2.shtml

 

How much RAM is reserved for your integrated graphics? 256MB's? With that card Windows does not show that amount as not available to Windows. Now we are up to 2686MB's. And with a Windows 32bit OS 3GB's is about the most you would ever see. Previous posts explain were some is. Microsoft has technical documents on this issue Google if you want, very dull read. I would not worry about it. One of the "fixes" is a bad idea as it gets rid of your system's ability to stop certain kinds of malicious code.