Photoshop RAM

[Charlie Woodrich]

I just purchased a new PC and I have 4GB of RAM. In PS CS3 preferences I am being asked how much RAM I want to set aside for PS. But it says that I only have 1674 MB of RAM, so I can't even allocate 2GB to PS. How do you fix this to have PS recognize the total RAM (I checked the bios and I have 4GB)?

[Chris Ober]

You need to add the /3G switch to the end of the line in the boot.ini. The file is readonly and hidden so make sure you disable the readonly attribute before and set it back when you're done editing.

Here's Microsoft's detailed information on it and their sample boot.ini.
http://www.microsoft.com/whdc/system/platform/server/PAE/PAEmem.mspx



timeout=30
default=multi(0)disk(0)rdisk(0)partition(2)\WINNT
[operating systems]
multi(0)disk(0)rdisk(0)partition(2)\WINNT="????" [B]/3GB

Adobe's tech note on memory usage - http://kb.adobe.com/selfservice/viewContent.do?externalId=320005&sliceId=1

[Robert Amoruso]

Thanks Chris. I knew I had this someplace but still have not found it.

[E.J. Peiker]

You need to add the /3G switch to the end of the line in the boot.ini. The file is readonly and hidden so make sure you disable the readonly attribute before and set it back when you're done editing.

That's only for XP - do not try this in Vista. A new PC most likely has Vista and this will not work in Vista. In Vista you simply click on Run and then type:
BCDEDIT /Set IncreaseUserVa 3072

Also in XP, just adding the /3G switch will in many cases cause a system lockup during Windows boot because you haven't left address space for the RAM that is installed on the graphics card. Unless you have internal graphics, you also need to add /userva=2700 or userva=2600 use the lower number if you have a graphics card with more than 256MB of RAM.

[Chris Ober]

Thank you.

[Charlie Woodrich]

Thanks guys. I think this is the one case where it's easier to do something in Vista than it is XP.

[Robert Amoruso]

Thanks EJ. Nice to get it from the originator. I finally dug this up during lunch. I had done this on my XP computers and of course not the Vistas.

[Adrian LeRoy]

In the 32-bit Windows world, XP or Vista, the most the OS will use is 4GB minus what must be allocated for "housekeeping." In this category are things like video card memory and a rough approximation is that it will all add up to 1GB. Thus, you'll get a maximum of about 3GB available including what Windows itself needs despite putting 4GB in your computer. Photoshop is smart and uses the 1GB of the original 4GB left over somewhat productively, unlike most applications. The only way around this limitation is to go to XP or Vista's 64-bit versions, which will cause numerous other problems, notably driver compatibility, perhaps surprisingly more an issue with 64-bit XP.

If this sounds vaguely familiar, it's the same issue that original PCs faced with 16-bit operating systems. Their limit was 1MB less the housekeeping amount, leaving 640K, a number that you may recall from 25 years ago, if you are old enough.

Bottom line: even if your PC can hold more than 4GB of memory, save your money right now.

[Robert Amoruso]

Good points Adrian. Thanks.

[Maxis Gamez]

I did the tutorial in my new Dell (4GB - with XP Pro) and works very well, now CS3 reads 2391MB and is very fast!