4GB of RAM - Don't waste your money!

[DreamThrall]

I'm sure this has been covered before, but I found this blog/article about why you won't be able to use 4GB of ram in 32-bit Vista (or any other 32-bit OS, for that matter). It explains everything pretty well, so I figured I'd share:

The 32-bit processors only allows for access about 4GB of total computer address space. So in a 512MB-2GB computer, you would have full access to the memory and there'd still be another 2GB of address space to hold device locations. Here is a little piece to the total 64-bit puzzle that no-one seems to be telling anyone about. In that 4GB of address space, your video card memory is partitioned. Meaning if you have a 256MB video card, 256MB is consumed in the 4GB of total addressable space that a 32-bit processor can utilize. Here's the problem; what if you have a video card that has 512MB, 640MB, 768MB? Yup, that will be mapped to the 4GB of addressable space. So if you had a 768MB NVidia 8800 card and 4GB of RAM, you'd lose 768MB of that 4GB of memory immediately to the device making it non-accessible "memory" for the OS. And it doesn't stop there, all of your other devices that need to be communicated with (you know, anything with a driver) consumes part of this address space. So in my current 4GB worth of RAM system, 1.25GB worth of addressable space is consumed by devices. And it gets worse.

Let's say you are one of those insane gamers (not that I've ever been accused of being such) and have bought into the whole SLi architecture. You run out and pick yourself up two of the 768MB 8800 video cards... guess what?

You would lose another 768MB of memory. Yes, this means that you would have a MAXIMUM limit of 2GB... EVER in the 32-bit world.

Clicky!

 

[DEATHMASTER]

Veeery old news.

 

[DreamThrall]

Veeery old news.

I'm aware.

 

[CptStern]

the new macs allow for 16g of ram ...yup that's right: 16 gigabytes

logical conclusion: pcs suck


/me runs

 

[Ravioli]

the new macs allow for 16g of ram ...yup that's right: 16 gigabytes

logical conclusion: pcs suck


/me runs

No games or hardly any application at all will ever fully use 16GBs...

 

[CyberPitz]

No games or hardly any application at all will ever fully use 16GBs...

They are preparing for the future...
the far..
far...
far....
far.....
far..........
future.

 

[CptStern]

No games or hardly any application at all will ever fully use 16GBs...

I disagree ..video audio work for one thing, plus the mac I was referring to is a workstation for controlling up to 8 30" lcds ....16g of ram gotta come in handy under those circumstances


contrary to popular belief games are not the only thing computers were made for

 

[DevgruSeal]

Right, but this is just for 32-bit CPUs, no?

The 64-bit versions and 32-bit versions of Vista are the same price. (At least on newegg.. USD$179) So the biggest problem here is using a CPU that has 64-bit architecture. And that's pretty widely available now.

 

[Sanada]

Some 32-bit CPU's (Pentium Pro and up) are capabable of having upto 64GB of addressable memory as they have a 36-Bit address bus. However, the OS needs to support PAE and XP/2000 doesn't so it's useless.

 

[Dekstar]

32-bit windows can only detect up to 3.25 gb correct?
I have 4gb of RAM, and a 640mb 8800, and I haven't noticed anything bad.

 

[The Brick]

3gb is still more than 2.

 

[Asus]

I'm pretty sure the 2GB limit is per process and with Virtual Memory. Then it gets mapped to either physical RAM or the hard drive (pagefile). And yeah, virtual memory maps to video RAM too.

And of course there is the /3gb switch which changes the 2GB OS and 2GB per process (applications) limit to 1GB:3GB. But while the user space has more room, the kernel space is more limited now.

If you think you could use the memory then go ahead and get 4GB, especially if you are buying a new PC. Meaning running a 64bit OS or more than 1 memory-heavy program in 32bit OS.

But did ya know most programs for Vista 64bit still limit themselves within the 2gb window for compatibility? Some detect the ability to use more but the others you have to flag it to use more. I think Anandtech had an article on that with games a while ago.

contrary to popular belief games are not the only thing computers were made for

I thought it was law...

 

[DreamThrall]

I'm pretty sure the 2GB limit is per process and with Virtual Memory.

No, I'm pretty sure it has something to do with the maximum size of a 32-bit integer, which is used to address the RAM itself, which is a much more difficult limitation.

 

[Top Secret]

So then get with modern times, and install a 64 bit os.

 

[Kula Meenur]

the new macs allow for 16g of ram ...yup that's right: 16 gigabytes

logical conclusion: pcs suck


/me runs

I'm chase after you you hedonistic bastard!



...anywho, why would you need that kind of power on a mac anyway? To make the computer crash faster?

 

[Asus]

No, I'm pretty sure it has something to do with the maximum size of a 32-bit integer, which is used to address the RAM itself, which is a much more difficult limitation.

MS page

In modern operating systems, including Windows, application programs and many system processes always reference memory using virtual memory addresses which are automatically translated to real (RAM) addresses by the hardware. Only core parts of the operating system kernel bypass this address translation and use real memory addresses directly.

Some commonly reported architectural limits in Windows include:

1. 2 GB of shared virtual address space for the system
2. 2 GB of private virtual address space per process