2gb vs. 4gb of RAM

[dmerger]

I have 2gb of RAM in my PC with Windows XP Pro.  I use Photoshop CS for my film scans, which are over 200mb.  With layers, my files are often over 1gb.  The slowest part of my work flow is opening and saving my images, and sometimes screen display is a little slow, although not a major concern.  All other aspects of CS are fairly fast.  I do run at less than 100% efficiency at times.  My scratch disk is a separate SATA HD.

I'm aware of the 2gb limit for RAM with Windows XP (32 bit), and I've read a little about an XP Pro modification to increase RAM usage (but I know very little about such modification).   Here is a link to a Microsoft explanation.  http://www.microsoft.com/whdc/system/platf...PAE/PAEmem.mspx  

I can add another 2gb of RAM for about $200, giving me a total of 4gb.  Would this increase provide a significant performance increase for CS?  Would I need to make the modification described in the Microsoft release?

[sergio]

I have 2gb of RAM in my PC with Windows XP Pro.  I use Photoshop CS for my film scans, which are over 200mb.  With layers, my files are often over 1gb.  The slowest part of my work flow is opening and saving my images, and sometimes screen display is a little slow, although not a major concern.  All other aspects of CS are fairly fast.  I do run at less than 100% efficiency at times.  My scratch disk is a separate SATA HD.

I'm aware of the 2gb limit for RAM with Windows XP (32 bit), and I've read a little about an XP Pro modification to increase RAM usage (but I know very little about such modification).   Here is a link to a Microsoft explanation.  http://www.microsoft.com/whdc/system/platf...PAE/PAEmem.mspx   

I can add another 2gb of RAM for about $200, giving me a total of 4gb.  Would this increase provide a significant performance increase for CS?  Would I need to make the modification described in the Microsoft release?
[a href=\"index.php?act=findpost&pid=52349\"][{POST_SNAPBACK}][/a]

Having more ram benefits, however for PS to access more then the 2gb you need to edit the boot.ini file
I couldn't do that succesfully, always crashed so I gave up. There's people here who have done it though. Run a search in the forum and you will find the thread.

[kaelaria]

The biggest problem with going over 2GB is the hardware.  Right now, on the majority of PC boards ram will not run at full speed with more than 2 sticks installed on the motherboard, or with multiple 2GB sticks.  Running over 2GB total most oftem means dropping the ram speed by up to 50% and backing down the timings (espeically the command rate from 1T to 2 or more) - which takes an AWFUL toll on system performance.  If you need a large ram machine, the best option is a mac, unfortunately.  And no, simply adding 1GB more of addressable ram to your system (3GB limit) would not improve things significantly for you anyway.  Going to 4 or 8 addressable (mac) would though.  From your limited description of workflow needs though, it doesn't sound like you need to do anything.  You might be spending $10,000 to save a couple minutes.

I would first consider a faster file system if you have bottlenecks reading and writing.  The best value right now is a SATA2 RAID0 array with drives supporting NCQ such as the new Maxtors.

[Mark D Segal]

Kaelaria, I'd appreciate if you would go to www.voodoopc.com (no, not a joke, real serious stuff for people who eat speed) and check their Omen series - I believe 221a for graphics work. It can be equipped up to 8GB of RAM (at very high incremental cost once above 4 GB, why I don't know), which I am given to understand can benefit Photoshoppers (large RAM cache) - regardless that Photoshop DIRECTLY addresses up to 3 GB-worth. I would be curious to know whether with Voodoo-Omen system architecture and hardware specs the machines are likely to slow significantly at higher RAM levels. Obviously one wouldn't want to buy more RAM to increase speed if the net effect is to reduce speed!

(I should mention I don't own one of these but have been contemplating.............and there are lots of choices on the specs)

[kaelaria]

I'm familiar with Voodoo, they've been around for years, along with Falcon, Alienware, etc.  Good stuff, WAY overpriced.  

This particular system used a dual Opteron board, which is the only way to get the extremely high ram counts.  It supports up to 24GB (Voodoo only sells to , however not at full speed.  That type of configuration is only meant for servers, where memory bandwidth is not as critical as memory size (mainly SQL Database servers).

The board Voodoo happens to be using for this system is the Tyan K8WE.  The large price jump from 4 to 8 that you see is due to 2 factors.  First, there are 6 ram slots on the board.  In order to use the 2nd bank of ram (slots 5,6), a 2nd cpu has to be present - so you add another processor.  2nd, with only 6 slots that means you need to use at least one 2GB stick - which are MUCH more than 1GB sticks due to no demand and low production.

The board technically supports up to a 4GB stick x 6 slot configuration, however the cost would be well over $10,000 in ram alone.  It also requires at least one registered stick (more expensive) and you want to match the setup, so that really means 2.  That is a drawback of the Opteron chips right now as opposed to normal Athlon chips, that do not require registered sticks (cheaper).

When all is said and done, Windows XP and Photoshop will not show you any benefit above 4GB.  Windows does not use more than a few hundred MB to run, and as you know PS can only use 3.  To utilize such a setup as this you need Linux, WinXP64, Win2k Advanced Server (or XP Server), and apps that can use the full amount (such as SQL Server).

[Mark D Segal]

Kaelaria, thanks for the as-usual knowledgeable explanation. WAY overpriced may well be so, (I agree), but when you look around at the mainstream vendors you simply don't find those high-powered combos of specs offered anywhere else, and these guys know it so they price accordingly - they are a somewhat arcane, small group of constructors with no competition from the Dells and HPs of this world. Hence, the way around it is to build one's own - but that comes at cost too - especially if one is a novice, or to find someone you know that you know you can trust to do it for your properly at a (lower) price - again a risk.

Now, on the subject of RAM usage, I've been informed (I believe reliably - but I'd like to hear your view on this) that for both MAC and PC, the 3GB RAM constraint on Photoshop relates only to what PSCS2 can access and use directly, but that the computer's O/S will seek to use RAM cache first once the 3GB is exceeded and more memory is needed - for example for large layered 16 bit TIFF files. Because RAM cache works much more quickly than hard drive cache, one has a definite speed advantage with available RAM beyond 3GB once caching becomes necessary, and the more RAM the better, as PSCS2 16 bit files with Photoshop, the O/S and background stuff running can use as much as 8GB RAM.

[kaelaria]

Windows does not use a 'ram cache' like that.  Other OS's do though.  The additional ram mearly sits unused, unaddressed.  The OS does not cache files coming in and out - it's not doing anything with them.  PS is the only app that would make calls to the ram buffers using, opening or saving a file.  If it worked the way you described, there would be no app limit, it would simply be a common ram pool for the whole system (not a feature of WinXP).

A simple test (which I have done) would be to take your current system (mine has 2GB ram), and note at boot, how much the OS uses.  Mine takes just over 300MB.  Next, use the PS ram allocation  slider to limit it to 25%.  That leaves you with (roughly) 512MB for PS, and 1.5GB (300 used) for the OS, with (roughly) 1.2GB free.  Now do a time consuing benchmark procedure (process a file, doesnt matter what) and note the time.  

Now, remove 1/2 your ram, move the PS slider to 50% and repeat.  That keeps the 300MB for the OS, keeps (roughly) 512MB for PS but now you only have 200MB free.  Run your benchmark again and you will find zero difference.  The exatra GB ram not specified addressible (by the slider or OS limitation) is not utilized (unfortunately).

[Mark Graf]

Having more ram benefits, however for PS to access more then the 2gb you need to edit the boot.ini file
I couldn't do that succesfully, always crashed so I gave up. There's people here who have done it though. Run a search in the forum and you will find the thread.
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I noticed a significant increase in speed by just going from 2GB to 3GB, especially when working with layers and 16 bit files.

For those of you having troubles with the 3GB switch and crashing, there is a fix posted here:  
This KB addresses video card problem.
[a href=\"http://support.microsoft.com/default.aspx?scid=kb;en-us;319043]http://support.microsoft.com/default.aspx?...kb;en-us;319043[/url]
http://support.microsoft.com/kb/316739/
This KB addresses possible hard drive corruption caused by the \3gb switch and lack of kernal space. Suggested workaround is the same.
http://support.microsoft.com/default.aspx?...kb;en-us;839490

[Mark D Segal]

Kaelaria, thanks, I'll take your word for it - had enough trouble in this Dell box getting the RAM sticks in and out - best I not mess around with it as you have already done it. I think the person who gave me the advice about the 8 GB is more tuned-in to MAC. Anyhow, I suspect 4GB RAM will be more than enough to make a huge difference relative to the 1.5 I now have on this Dell 8200 (from 2002, Intel P4 as we've discussed before) - haven't changed it yet - the big plunge is yet to come - I know I'll get better performance, but the mere thought of re-installing everything only to know it will be "outdated" within a year makes me hesitate.

[Mark D Segal]

I noticed a significant increase in speed by just going from 2GB to 3GB, especially when working with layers and 16 bit files.

For those of you having troubles with the 3GB switch and crashing, there is a fix posted here:  http://www.naturescapes.net/phpBB2/viewtopic.php?t=54998
[a href=\"index.php?act=findpost&pid=52649\"][{POST_SNAPBACK}][/a]

Can't get into it without registering. Any other way to get that info for future reference?

[Mark Graf]

Can't get into it without registering. Any other way to get that info for future reference?
[a href=\"index.php?act=findpost&pid=52652\"][{POST_SNAPBACK}][/a]

Sorry Mark, I edited my original post to other links in the Microsoft Knowledge base.

[kaelaria]

Anyhow, I suspect 4GB RAM will be more than enough to make a huge difference relative to the 1.5 I now have
[a href=\"index.php?act=findpost&pid=52651\"][{POST_SNAPBACK}][/a]

Yes it sure will.

[Mark D Segal]

Sorry Mark, I edited my original post to other links in the Microsoft Knowledge base.
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Thanks Mark. Got it.

[budjames]

I just upgraded the RAM in my Dell dual Xeon processor Precision Workstation 470 from 2GB to 4GB.

Photoshop did not recognize the additional RAM until I edited the boot.ini file in WinXP Pro SP2 by adding the 4GB switch. The line of code added is "/4gb".

After rebooting, PS CS2 now had almost GB of working RAM. Filters run a bit faster when having multiple windows open in PS.

I can't wait for the retail release of WinXP Pro x64 so that I can really take advantage of the dual processors and go beyond 32-bit's memory limit of 4GB.

Bud James
North Wales, PA

[Bikedude]

Photoshop did not recognize the additional RAM until I edited the boot.ini file in WinXP Pro SP2 by adding the 4GB switch. The line of code added is "/4gb".

Uhm...

Read http://blogs.msdn.com/oldnewthing/archive/.../17/215682.aspx first.



(sorry for this late reply, but someone recently made me aware of the misinformation being bandied about)

That said, from reading other postings on that blog, I get the distinct impression that using /3GB is a very bad idea. (it limits the kernel memory from 2GB to 1GB for one thing) I suspect most will find 64-bit Windows (and hunting for device drivers) much less hassle than /3GB. (which is only there for specific purposes, and running PS was most likely not one of them) Or simply put: If /3GB was only a good thing, it would've been enabled by default.

The second issue at hand is that XPSP2 is limited to 4GB physical memory. On top of that, PCI/PCIe/AGP hardware devices map their memory below that limit. So you face another issue: Memory hole. You memory controller has to remap part of its memory above the 2^32 address space. XPSP2 can't benefit from that. Although XP supports PAE (needed to enable DEP support), it does NOT actually use the address extension mechanism provided! (because many drivers would be confused faced with a 64-bit address space)

On my rig, 4GB is thus cut down to 2.75GB, using 32-bit XP that is.

So in conclusion, if you have 4GB memory (or more), your choices are either 32-bit Windows Server 2003 or 64-bit Windows. In either case, you run into problems with device drivers. E.g. the latest ForceWare 8x.xx drivers from nVidia do not run flawlessly on 32-bit Windows 2003 loaded with memory (version 79.11 OTOH does). And 64-bit Windows is still haunted by missing third-party drivers (for printers, scanners and many consumer type devices).

PS CS2 behaves very nicely under 64-bit Windows though and certainly benefits from having extra memory.

[budjames]

I would love to upgrade my workstation OS to Win XP Pro 64 bit, however, Norton antivirus, Monaco EZ Color (monitor calibration) and other important utilities are not yet 64 bit compatible.

No point in having a faster Photoshop CS2 experience if you can't get the colors right.

I guess the Mac folks are ahead on this one.

Bud James
North Wales, PA.