memory allocation

blue chuzzle

i just upgraded my pc from 1 to 3 gigs of ram.

i spent a while reading about the /3GB switch and it seems that it will allow a very limited number of programs access more than about 1.7 gigs. what is the other gig doing??

now that im using 4 slots instead of 2 do i have double the bandwidth from memory to the processors?

also im using XP media center edition, not professional. is the 3GB switch supported?

Thanks...

blue chuzzle

*bump*

i was told by the tweakers and modders you guys could help!

dont let me down...

Capt'n Midnight

As to what the other RAM is used for..

OK, let’s do some simple math. If I have five applications running and each applications uses 1 GB of virtual memory, then I am using 5 GB of virtual memory. However, each application only uses 1 GB of virtual memory and doesn’t come anywhere close to using its allotted 2 billion virtual addresses. Using the /3GB switch would change nothing in this scenario.

so your worry about an app not being able to see all the ram only applies if you are only running ONE program including all the windows processes.

On the other had if you have an application that actually needs lots of memory ( > 2GB ) to run in.
http://www.microsoft.com/whdc/system/platform/server/PAE/PAEmem.mspx

Windows XP Professional and Windows Server 2003 Memory Support. The maximum amount of memory that can be supported on Windows XP Professional and Windows Server 2003 is also 4 GB. However, Windows Server 2003, Enterprise Edition supports 32 GB of physical RAM and Windows Server 2003, Datacenter Edition supports 64 GB of physical RAM using the PAE feature.

so you have to buy a more expensive license if you want to use more than 4GB of RAM

However, it would be ineffective to automatically provide every application with a 3-GB address space.

Executables that can use the 3-GB address space are required to have the bit IMAGE_FILE_LARGE_ADDRESS_AWARE set in their image header.
..
Some manufacturers preconfigure their applications to use application memory tuning, making it unnecessary for you to make this change. For more information, see your application documentation and contact your application vendor to determine whether they support Large Address Awareness or whether you can enable it in their application.

then again on a PC with 1GB of RAM and a 3GB swap file when you run out of physical ram you use the hard drive swap file and so could run very large programs, although, extrememly slowly, even they could not fit in ram all at the same time

blue chuzzle

yea, i wanted photoshop to see all 3 gigs. i dont think many people would have 2 programs open at the same time that use a significant amount of memory(ie more than 1 gig)

i might install xp pro to see if that makes a difference, i have a licence from a broken laptop.

Capt'n Midnight

Don't forget you can't move an OEM license, it lives/dies with the hardware, the exception is when the HW is replaced under warranty.

http://www.adobe.com/support/techdocs/332271.html - only mentions >2GB on 64bit machines - check your version of photoshop or call adobe to get the best settings.