Sigh… Nearly all 32 bit operating systems divided the virtual address space into two halves. One of the 2GB address space is reserved for the operating system (it gets mapped into every program’s total of 4GB). The other 2 GB is available to the program.
Jim wrote in message
I just plugged a new machine in, P4 with 4GB of RAM, and Photoshop 7 is
only recognizing 2GB. Is this an inherent limitation? What’s up?
Because of this 32bit OS-based limitation, unless you intend to run some other memory intensive processes at the SAME time as Photoshop, I recommend creating a RAMDISK of 1gB at least and assigning that as the first Photoshop scratch disk..
Keep in mind that under some conditions, with come CPU setups, even with more than 2 gB ram, allocating more than 50% of available memory in the Photoshop preferences CAN cause system slowdowns, and you may find Photoshop running more slowly..
At one point, some were told that turning off Multi-threading would help, but now the suggestion seems to have solidified to allocating less than 50% in the preferences if your system seems to have problems.
I’m not sure if Adobe has changed its recommendations on this.
I think the majority of users who’ve run into issues with memory settings/performance have been running at or below 2Gs total RAM. The suggestion for the user should be to tweak the memory setting to the point wherethey are satisfied with Photoshop’s performance. The general advice I’ve seen given is to move the setting down in 5% increments. Hyperthreading should have no impact and AFAIK was a (bad)workaround given for an MP specific issue.
Thank you all for your thoughts on this. The machine is new and much faster than what it replaces so speed difficulties may be hard to detect. Right now I am allocating ALL of the apparent ram to Photoshop, about 1.8G. I am intrigued by the RAM disk, I thought that was only a mac thing. This would imply that the other 2 GB would be available to the OS? And then PS would see this as a scratch drive and not RAM? Very cool if it works. Where do I go to set this up?
I don’t mean to start an arguement here, but I seem to recall that Chris Cox has commented in the past that a RAM-disk does not help PS performance. :O
If he or anyone else did, I’d suggest he/she look at the tests I ran which do show increased speed, or run his/her own tests. I ran the tests soon after installing CS. (They were posted here already, so I’m not about to go dig them out again.) It’s a simple fact that if a faster hard drive makes a difference in scratchdisk performance than a RAMDISK will do the same, as its faster than ANY hard drive.
If you’ve got a large amount of RAM on a machine that PS can’t access as part of the application process, Adobe has recommended, as far back AT least as V3, that one create a RAMDISK to use as a scratch disk. Hell, I was at MacWorld sitting in on the Adobe Photoshop seminar in the early 90s when they gave out the first cloud filter to seminar attendees and recommended EXACTLY that.
The same issue we are dealing with now: where an application and/or the OS cannot, in some instances of advanced hardware, access all the available on-board memory, or even extra memory in plug-in ram boards, happened when OS’s were in a transitional state from 16 to 32 bit architectures.. Heck.. There were and ARE add-in cards for WinTels and Macs that were/are simply ram mounted on a board to be used as a RAMdiak. At one time they were quite common on many high-end graphics machines that were being used for Photoshop in service bureaus etc..
Beyond which, PhotoBug, someone saying that "Chris Cox said such and such" is nothing but hearsay or gossip unless you can provide a link to the comment..
Chill-out Keith… I expressed an honest belief without any personal attack upon you or your credibility. I didn’t want to start an arguement (as I clearly stated in my post) and I was just expressing what I sincerely believed Chris once said (before CS was released).
Thanks for the sanity-check Dave. I was pretty sure about that comment by Chris (and as I recall, it was applicable to PS7).
Well, a RAMDisc is not going to help if you are starving PS of available RAM to set one up, and I seem to recall him commenting on that.
That situation is inapplicable when you’ve already maxed PS’s RAM. A RAMDisc or something like the hellishly expensive RocketDrive is a great way to speed up the scratch disc.
That situation is inapplicable when you’ve already maxed PS’s RAM. A RAMDisc or something like the hellishly expensive RocketDrive is a >great way to speed up the scratch disc.
What I have right now is 2 striped drives for data, 2 striped drives for the scratch file, and 4gb of RAM. Do you think it would be better to leave alone the other 2g not usable by Photoshop, or make a 1g RAM disc? Photoshop is the only thing this machine is used for.
I guess the ideal situation with your hardware setup, Philip, would be to keep the total scratch size low enough so that you only write to the ramdisk and not to the hard drives. That might mean lowering history states, tweaking other options, and finding workarounds to generating new layers. If you end up working multi-gigabyte files, the 1 gig ramdisk gets sucked dry quickly, and thereafter as you manipulate the image, the hard drive scratch disk is the limiting speed factor.
keep the total scratch size low enough so that you only write to the >ramdisk and not to the hard drives. That might mean lowering history >states, tweaking other options, and finding workarounds to generating >new layers. If you end up working multi-gigabyte files
The point of upgrading to this machine is to accomodate very large files, as it is part of the workflow here. It sounds like a 2 gb ram disc, or not at all, eh?
A worklfow scenario might include editing 16-bit large-format transparency scans. After one such file is opened and the background layered copied a few times, the scratch size could easily be pushing 3 gigabytes. Concurrently opening another similar-sized file for compisiting, merging, or color matching purposes, and the 1 or 2 gig ram disk is long since full and you’re back to writing to the hard disk scratch. If the editing session lasted an hour, scratch sizes could top 20 gigs. For a relatively short time, the ram disk sped up operations.
For solely Photoshop work, it may be faster to RAID all 4 hard drives onto one controller, rather than spread them over 2 RAID controllers, as you currently have configured. The argument being that majority of I/O is for scratch use and not data or OS operations. The latest crop of 875/865 Intel motherboards come equipped with 4 or 6-channel RAID controllers in addition to the built-in 2-channel Intel controller.
A faster but more expensive solution (up-front cost–depending on how much of your day is spent twiddling multi-gigabyte images) would have been to go with a dual 64-bit AMD processor board packed with 16 gigabytes of ram, and several of those solid-state ram hard drives eluded to earlier by another poster in this thread. PSCS can’t take advantage of a 64-bit OS yet, but a ram disk program could access the extra ram.
Fwiw, I work with fairly large files and my PS comp (which consists of a P4 2.8C, 1GB of dual-channel RAM, and 2 HDDs on separate IDE channels) is pretty darn ‘zippy’! So I sure don’t understand the need for much more ‘fire-power’. (?)
So I was aware of the 2GB app limit, but after just upgrading from 2 to 4GB RAM, Photoshop still only sees 2GB, as expect, but it seems a bunch of that 2GB used (almost 400MB worth). I presumed it would see 2GB free that it could use (i.e. 100% allocation to photshop). The system reports only about 420MB used total from the 4GB.
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