Down sides of 4GB in a 32bit system?

[Funkstar]

Other than the inability of a 32bit system to see all 4GB of RAM, are there any other down sides?

Had a look the other day and Scan have 2GB Corsair SO-DIMMs for only £71.21. Less than half the price since i last looked.

I have 2GB in this laptop at the moment, and with Vista Business i think i'd see an improvement with 3.5GB, especially when using Adobe Lightroom and Photoshop.

[staffsMike]

No disadvantages other than that no

[Funkstar]

Thats what i though, but wanted to check just in case

[vinnyT]

Other than you've metioned I don't thonk so. But, I do have a question, would the mobo still run the ram in dual-channal mode?



Edit: Sorry guys, just realised that the dual-channal bit has nothing to do with the OS (and what it can and cannot register re ram). I'd put it down to drink, but I don't.

[directhex]

remember there's a 2gib limit on a single app

[DataMatrix]

Other than you've metioned I don't thonk so. But, I do have a question, would the mobo still run the ram in dual-channal mode?

Yes. If it's 2x2GB it will. If the motherboard supports 2 sets of dual channel (4x1GB) it also will.

[Agent]

Guhh, not the Dual Channal thing again

The only possible downstide is the timings might need to be slackened. This rarely has any 'real world' effects though (and the advantage of more RAM usually outweighs them )

[Funkstar]

remember there's a 2gib limit on a single app

Indeed. But it does mean that Photoshop (for example) can take its 2GB and Vista still has a load of RAM to play with

I think i'll place an order sometime this afternoon.

I was going to ask about peoples opinions on Kingston vs Corsair, but then the Kingston modules are not in stock anyway.

[Gr44]

Sorry for the slight thread steal. But why is there a 2GB limit per app? Seems a little odd, surely we can't be that far away from games needed more than 2GB ( or atleast being able to use 2GB? )

[Agent]

Sorry for the slight thread steal. But why is there a 2GB limit per app? Seems a little odd, surely we can't be that far away from games needed more than 2GB ( or atleast being able to use 2GB? )

Its more to do with the limits of 32bit addressing.
There is ways that an app can user over 2GB (Even on windows 32bit), but the prerequisites are very very specific. So specific that it will just not happen for home users

64Bit windows does not have the 2GB limit

[Funkstar]

64Bit windows does not have the 2GB limit

Does the limit dissapear whith a 64bit OS, or does the app need to be 64bit as well?

[Agent]

The app needs to be using the 64bit data path (ie, 64bit).

A 32bit application is only compiled with information of the 32bit registers, thus can't use anything above that into the 64bit range.
While I know someone is going to point out that 32bit ha s a limit of 4GB, I am 99% sure that even Vista 64bit limits 32bit apps to 2GB of memory addressing space for backwards compatibility.

[moogle]

Does the limit dissapear whith a 64bit OS, or does the app need to be 64bit as well?

with a 32 bit app in windows x64 it can use up to 4gb, so yea it does dissappear, but its still limited to its 32 bit (4gb) addressing. but the app can only access 4gb if it has the LAA flag enabled (IMAGE_FILE_LARGE_ADDRESS_AWARE)

[Agent]

with a 32 bit app in windows x64 it can use up to 4gb, so yea it does dissappear, but its still limited to its 32 bit (4gb) addressing. but the app can only access 4gb if it has the LAA flag enabled (IMAGE_FILE_LARGE_ADDRESS_AWARE)

But that was only of any use on a 32bit system that supported PAE, allowing 36bit addressing of the memory registers.
XP had PAE disabled (IIRC it was SP2), so the chances that any app's running under it have this flag are very minimal.
Only specialist software would have it, even then, it would have been aimed at Windows server 2003 / x64 like you said

In short: 99% of app's will still have the 2GB limit. If you don't know if the app has LAW, its almost certain it doesn't

[Funkstar]

Thanks guys. Makes no difference to me, but intresting none the less.