Why Ram is being used less in Win7? Help

I have 2 laptops with X86 Win 7 RC. In my XPS M1730, it shows 3 gb usable and in another laptop which is XPS M1330, it shows 3.5 usable. I dont know what's wrong or I need to do something to make 1/2 gb usable?
Any help

Thanks

 

The hardware (like GPU) might have more RAM allocated.

 

Umm, have you taken a look at what's running in each? Also, have you taken into account that one has to drive a 17" 1920x1200 res screen (2,304,000 pixels), while the other only has to drive a 13" 1280x800 screen (1,024,000 pixels)?

 

x86 = 32 bit, which means that you will not be able to use all 4GB if you have 4 installed.

 

I know that it cannot use 4gb. But in my XPS M1730 with 98m SLI, it shows 3gb usable and in M1330 with 8400m, it shows 3.5 gb usable. So whats up with these two differences?

 

Chipset limitation may be the cause

 

Well, first off, the chipsets in both of those systems almost certainly have a logical address space of 4GB (it was only very recently that laptops started coming with larger logical address spaces). This is an aspect of the chipset that is hard-wired.

What it means is that the computer only has 4GB worth of addresses it can assign to everything that needs to be addressable by the CPU or some other component on the system. In particular, each byte of physical video RAM on the GPUs has to be allocated a logical address from out of this pool of 4GBs' worth of addresses. That means that there is always strictly less than 4GBs' worth of addresses to allocate to all other components, including the physical RAM. That, in a nutshell, is the reason why most 32-bit Windows systems can effectively only use about 3.5GB of a 4GB set of RAM modules.

In your case, the .M1730 has 1GB of dedicated video RAM on those 9800M GPUs, which means that, out of 4GB of logical addresses, only 3GBs are left over to allocate to everything else when all is said and done.

Actually, doing the math, I'm going to assume that what you have are two 9800M GPUs in SLi, each card having 512 GB of RAM - that will be the number of logical addresses assigned to the GPUs in your system (because of the SLi configuration, the system only "sees" the video RAM on one of the two cards).

That would leave about 3.5 GB of logical addresses to allocate to everything else. You probably have about 512MB of addresses allocated to things like your USB ports and whatnot, which would leave you with only about 3GBs of logical addresses left to allocate to your physical RAM. And that is what you are apparently seeing.

By contrast, the M1330, with the 8400M GS, only has 128MB of dedicated video RAM, which means it only needs to allocate 128MB of logical addresses to the video card, leaving it with 3,968MB, or 3.968GB of logical addresses to allocate to other components. Since it probably doesn't have as many components as the .M1730, it doesn't need to allocate as many logical addresses to non-RAM components. So, in this case, you probably have about 456MB or thereabouts assigned to non-RAM components, such as USB ports, and that would leave you with about 3.5GB of logical addresses to allocate to your RAM, which is more or less what you're seeing.

 

damn.... what a great explanation but crossed my mind.

Thanks for the info!

 

thx for the info

 

I would install a 64-bit OS if you do not need 32-bit (and 16-bit) programs. It is rumored that the next version of Windows "8" will be 64-bit only.

 

Already with the Windows-8? Windows-7 isn't even officially out of the gates yet.

 

If Windows 8 hits the shelves around 2013, 64 bit mainstream processors will have been available for barely a decade. Maybe that's long enough? Probably not.

 

Ya, after Windows 8, it will be Windows 1 coz of destruction from 2012 Dec 21.