2GB v 4GB Query

LiamJH · 7 Nov 2006 at 07:30

Would there be a noticeable performance improvement from having 4GB of (probably Geil) 6400 (4 x 1GB) running on my Asus P5W DH over having 2GB installed? Are there any known issues of running 4GB on this board?

Machine is used for varying things from encoding, rendering to gaming...

Thanks

w3bbo · 7 Nov 2006 at 08:02

It depends what OS you plan on running.

XP32bit will only recognise upto 3gb. XP64bit will recognise the 4gb as will vista. If you have xp32bit then having 4gb of ram is pointless.

LiamJH · 7 Nov 2006 at 08:07

Well it was going to be xp (32-bit) until Vista came out...

richardg3 · 8 Nov 2006 at 17:44

There's also the fact that in XP and 2000 a single process (application, game etc) can only address up to 2GB unless its specifically coded to address higher (pretty much nothing is due to paging complexities). Hence the 3GB implied limit - gives your game/app 2GB and allows extra for other proccess, OS etc.

I think 4GB is the limit for any 32bit OS. If you go with XP64 or Vist64 that limit then becomes 128GB. Under a 64bit OS if it recognises less than the adressable 128GB then its the motherboard that doesn't support it.

I've heard that gaming under Vista will allow you address 4GB of ram without the 2GB the limitation. I can't remember if that was only on the 64 bit version or not, although I would expect it was.

Simon D · 10 Nov 2006 at 19:13

richardg3 said:
There's also the fact that in XP and 2000 a single process (application, game etc) can only address up to 2GB unless its specifically coded to address higher (pretty much nothing is due to paging complexities). Hence the 3GB implied limit - gives your game/app 2GB and allows extra for other proccess, OS etc.

I think 4GB is the limit for any 32bit OS. If you go with XP64 or Vist64 that limit then becomes 128GB. Under a 64bit OS if it recognises less than the adressable 128GB then its the motherboard that doesn't support it.

I've heard that gaming under Vista will allow you address 4GB of ram without the 2GB the limitation. I can't remember if that was only on the 64 bit version or not, although I would expect it was.

When I was testing Vista beta 32 bit, it could see the extra memory, but on the RC1 release only address 3GB of ram.

No problem with the 64bit O/S full 4GB seen

james32 · 12 Nov 2006 at 00:24

Simon D said:
When I was testing Vista beta 32 bit, it could see the extra memory, but on the RC1 release only address 3GB of ram.

No problem with the 64bit O/S full 4GB seen

yes i tried vista 32 latest build and it shows only 3gb of ram

looks like 32 bit vista will be aimed @ people who dont need more than
2gb of ram i.e laptops.

drak3 · 12 Nov 2006 at 01:45

The chip can address 4GB and every application can use 4GB, but they set the limit to make room for the kernel

m3lv1n · 12 Nov 2006 at 14:36

There are very few apps on a 32bit OS that will address more than 2GB RAM Photoshop CS2 is one of them. You can use the following boot switches on your boot.ini to tweak for your system

/3GB this switch allocates 3 GB of virtual address space to an application that uses IMAGE_FILE_LARGE_ADDRESS_AWARE in the process header. This switch allows applications to address 1 GB of additional virtual address space above 2 GB.

/USERVA=integer with this switch, you can customize how the memory is allocated when you use the /3GB switch. The number following /Userva= is the amount of memory in megabytes (MB) that will be allocated to each process. If you set /3gb /Userva=3030, this reserves 3,030 MB of memory to the process space, as compared to 3,072 MB when you use the /3GB switch alone. The 42 MB that is saved when you set /Userva=3030 is used to increase the kernel memory space, free system page table entries (PTEs). The PTE memory pool is increased by the difference between 3 GB (specified by the /3GB switch) and the value that is assigned to the /Userva switch.

To be honest unless you are running an application that is compiled with IMAGE_FILE_LARGE_ADDRESS_AWARE in the process header its a waste of time having more than 2GB RAM. If you are a gamer 2GB will be fine.

fumbles · 12 Nov 2006 at 16:48

IIRC 4x1GB will run at 2T, so just have 2x 1GB, its more then enough.

[EDIT: Whoops]

Sin_Chase · 13 Nov 2006 at 02:22

fumbles said:
IIRC 4x1GB will run at 2T, so just have 1x 2GB, its more then enough.

Or 2x1GB on Dual Channel