Topic: Windows 7 or 8?

[-<WillyP>-]

Hmmm. I had done some research on editing XP to unlock more than 4gb, and from what I read I concluded that video ram shares addresses with main ram. This was given as the reason why, if you have 4gb of ram, windows will report less than 4gb, because it does not report video ram.

[Foil]

In systems with integrated GPUs (e.g. on-the-motherboard), yes, the GPU shares the main ram.  But from your description of the machines, my understanding was that you had a separate graphics card in each, and those have their own non-shared memory.

[-<WillyP>-]

I see, that makes sense. Yes the cards are separate. I'll have to find what I read and re-read it.

[Matthew]

I though Video memory (even on discrete cards) still shared the same addressing limits as the main system RAM? At least that's what I was told when I was still using 32-bit Vista.

[Foil]

Yes, the addressing limits are the same (e.g. a 32-bit address space = 4Gb minus overhead), but I believe they're still separate.

[-<WillyP>-]

Ok i have done some further research and have a better understanding of How It Works.

While video memory is kept separate* from main ram, it still needs to be addressed, and there are only enough addresses in a 32 bit OS for 4gb. Windows allocates those addresses first to the video ram, then to main ram. So, my 16gb main ram plus 2gb video system with a 32 bit os, is running as 2gb main and 2gb video. Windows 7 home 64bit has an arbitrary limit of address space for 16gb, so it would be like having 14gb main ram and 2gb video. Pro raises this cap, allowing 192gb addressing, still a bit shy of the theoretical limit of 16exobytes for a 64 bit machine... But then there are physical limits also, but I think 16gb plus the 2gb video will suffice for a long time to come.

*separate in this case means data intended for main ram cannot be stored in video ram, and vice-verse.

[Foil]

Windows allocates those addresses first to the video ram, then to main ram.

Really?  I didn't think that was the case.  I thought they were kept in separate address spaces (i.e. a 32-bit OS could theoretically have a 4Gb ram space and a 4Gb vid-ram space, each minus overhead of course).

Now I'm really curious; would you mind pointing me to that info?

[Matthew]

Windows does NOT count video RAM against the main system RAM total, as it's only an arbitrary licensing limit and not a limit of the technology.  Only in 32-bit windows will you run into that issue (Unless you've managed to construct the world's first system to have multi exabytes of memory, and hacked windows to remove licensing restrictions.)

[TechPro]

It is my understanding that the only time video RAM is counted against (or "in" if you will) is on hardware that uses shared RAM which is a technique used by some manufacturers to artificially increase video RAM without increasing hardware costs, typically only done with 'integrated' video.  Actually a pretty common practice among low cost or 'budget' systems.  I have a couple systems that do that. Typically the amount of video RAM is small enough to be not too significant against the total ram left over for the OS.

Systems where the video card has it's own physical RAM (and that RAM is on the video card) do NOT do that. 

Either way, ANY 32bit OS really can only address and use about 3gb of RAM (I forget the precise number) but can show 4gb exists ... But does not actually use all of it without some memory tweaks. ... The 32bit OS is incapable of mathematically computing that high in order to use it. Thus 4gb and higher is only actually usable by 64bit OS systems.

I too would be interested in seeing the info WillyP got ahold of.

[-<WillyP>-]

Windows does NOT count video RAM against the main system RAM total, as it's only an arbitrary licensing limit and not a limit of the technology.  Only in 32-bit windows will you run into that issue (Unless you've managed to construct the world's first system to have multi exabytes of memory, and hacked windows to remove licensing restrictions.)

We are talking about the limit in 32 bit OS, specifically XP. Or originally I guess we were talking about 7, in this context Home (32bit) vs Pro (64bit) Sorry, I didn't make that clear in my earlier post. There are 32bit OS's that address more than 4gb, even some Windows products, mostly intended for servers. I believe Linux generally has no arbitrary software cap, though that may vary with flavor.

As far as a source, I Googled and got a lot of hits. A lot of argument was made for both views, but the most credible information, in my opinion, was that there are 'x' number of addresses (4gb, minus overhead) in a 32 bit system running XP, and they are allocated, by the OS, to video first, main ram second. Pointer to the ram on a video card are installed in the main ram, thus a portion of main ram is not usable.

And yes, of course it is a license limitation, if you do the math IIRC 32bit = 128gb. There are hacks I have read about that allow XP to address greater than 4gb, but that was way over my head.


I just Googled these up:
[Solved] Memory in Windows 7 - Graphics-Cards - Graphic-Displays
TechNet Blogs
64 bit - Why does installing NVidia 9600GT graphics card, take 1GB of RAM away from Windows? - Super User

The bottom line is, every device needs a unique address. That applies to memory, whether it happens to be on the motherboard or on a video card.

[Foil]

...if you do the math IIRC 32bit = 128gb.

No.  "32-bit" = 2^32 unique values = 4,294,967,296 = 4Gb.  That's all a 32-bit space can address.

[Edit: Ah, I see where the 128Gb comes from, in that TechNet link.  That's actually a virtual address spacing system that certain versions of Win Server 2003 32-bit uses.  It essentially uses the first 980Mb of the system ram to create a "map" into a larger-than-32-bit address space.]

There are hacks I have read about that allow XP to address greater than 4gb, but that was way over my head.

Maybe there are hacks for certain apps, but XP 32-bit simply cannot address a space more than 32 bits, or 4Gb.

----------

Okay, so I took a look, and found a very good WDDM doc for Vista/7/8: http://download.microsoft.com/download/9/c/5/9c5b2167-8017-4bae-9fde-d599bac8184a/graphicsmemory.doc

Basically, there are two scenarios:

1. Discrete graphics adapter (e.g. PCIe) ram, separate from system ram.  These are two separate memory spaces, and the OS will map some portion of system ram to gpu ram (how much seems to depend on the os and graphics drivers, but it does not have to be the entire size of the gpu ram) for transferring data.

So, for example, if you have a machine with 2Gb system ram, and a discrete gpu with 1Gb ram, the system can use 2Gb minus whatever it allocates for the transfer-mapping (could be the full 1Gb, but it's often more like a couple hundred meg for transferring textures, etc.).


2. Built-in graphics adapter (e.g. on-board), where the system and gpu both share the same memory space.

So, for example, if you have a machine with 2Gb system ram, and the gpu takes 1Gb, then the system can only use the remaining 1Gb.


...Does that make more sense?

[-<WillyP>-]

Close enough for me!  I am pretty sure I am wrong about whatever I said.

Anyway, I'll be picking up a check tomorrow, as soon as it clears I am going to order, I have decided on W7 Pro.

And a new chair too. This one sucks. And I think I'm going to get one of these: Unicomp, Inc. Ultra Classic Black Buckling Spring USB

[Foil]

Nice! 

[-<WillyP>-]

Strangely enough, my son got a new laptop yesterday with Windows 8. He hates it, but hasn't really tried to figure it out. But you know, shouldn't have to. I kinda like the tiles having active content in them, but then you have to scroll sideways to see them all. Not good! So trying to figure out how to do this or that and it seems like the whole theme is a thick layer of sugar coated prettiness designed purely to keep you from changing the setup it came with. But I haven't screwed with it much, my wife is trying to figure it out. So I don't know whether it really is as unclear and unintuitive as it at first seems, or if it's just a case of learning how to use it.

She just figured out how to get Norton to run a scan, so there is hope.  Of course, it would have been nice had she figured out, or been told by Norton, to update virus definitions first.

He had gotten a laptop with 7, but the video wouldn't run Minecraft at all. So my wife got him a new one, and the Geek Squad said this one would run Minecraft, so it must be true... 

[Foil]

One my one Win8 box, it took a little while to get used to the tiles.  Once I did, though, I found that I enjoyed it a bit.  Most of the time, I'd just hit the "Desktop" tile to get to the Win7-style area, but otherwise it was nice to arrange (and color) my tiles the way I wanted them.  I got tired of the side-scrolling, so I cut it down to just the tiles I *really* wanted, which fit on one page.

You're right, it's definitely a layer of saccharine prettiness, but it's not too bad.