Questions about Postscript printers and if additional memory is useful

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Okay, i figure this is probably one of the best places where i will get a good answer.

Basically on experts-exchange a guy and I are disagreeing about adding memory to postscript printers.

A person orginally asked a question regarding his current postscript printer. He has a laserjet 4ml which is a older postscript printer with 4 megs of ram which does 4ppm (at best). Anyway he is printing from an old beige g3 with os 8.6 or 9 i belive using the laserwriter driver.

Anyway, the issue at hand is that when he prints large complex pdf documents (ranging from 1 meg to 3 or 4 megs in size) it bogs his computer way down. He can barely do anything until the job is complete and porints. Then control is restored to the computer and he can continue.

Well I suggested that he replace the 4ml with a 5M which is a 12 ppm 6 meg base postscript laserjet. But i also suggested that he max out the ram so that he ends up with 52 megs of ram on the printer which i theroized would help restore control of the computer since the mac can spool all the data from the print jobs to the printer with having a lot of memory. My theroy is that the 4ml was bogging down with only 4 megs of memory on the large postscript jobs.

But this other tech is disagreeing with me. His statement is as follows:

Quote:

" agree with the comments on the 5m, but I'm afraid I have to disagree with the RAM issue. In general, adding extra RAM to a PostScript printer does not change the speed at all. Neither does it let the printer process more complex or larger documents.

A PS printer processes commands one at a time and cannot use more RAM to process that command faster. Once the command has been processed it is discarded, freeing up the RAM used."

He also states this:

Quote:

"Yes, what I am saying is that "a huge postscript document made up of complex tiffs and eps images and whatnot will take just as long to print and it won't hog the computer's resources while its spooling". It really is as simple as that. Note that, if you are using PCL (HP's printer language) there are reasons for adding extra memory; but with PostScript, once you have enough, any more is overkill.

First of all, the spooling is done by your PC (and/or the server). When you click on "Print", the application creates a print file. Once that is done, the PC is free to do whatever it wants. Spooling that file onwards takes a negligeable amount of processor power."

So my basic question is this, is adding more memory to a laserprinter (say over and above the 6 megs of the base 5m) overkill and won't make a difference when printing to the 5m from an old beige g3 using the laserwriter driver?

And if you do answer, i would like it to be somewhat detailed only because this gentleman has a lot of experience and points on EE and i am disagreeing with a "guru".

If I am wrong then thats fine, i learned something new about Postscript.

thanks...

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dankephoto's picture
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big files need big ram

the larger the file, the more ram needed. The printer's RIP (in this case the printer's built-in processor) stores all that raster data in RAM (assuming RIP has no HD) and if there ain't enough the RIP will choke. If there's more RAM than needed the printing won't go any faster, but if there's less than needed either the file won't print or it'll take much longer.

Some printers, your's included IIRC, use various compression schemes to handle jobs that otherwise couldn't fit into RAM, but of course that sort of trick costs processor cycles (time that is.)

RAM is also used by the RIP to run, and also to store fonts. Many printers cache fonts so they don't have to be DLed again for each print job, the more RAM the more likely a font won't get flushed to make room for a print job's raster images. Font caching is less important with modern ethernet equipped RIPs, but can still speed up the over all process when they can remain local to the RIP.

Is this contrary tech to whom you refer a hardware service tech or a graphics expert or what? While I'm no graphics expert I've certainly experienced the results of having insufficient printer RAM in a PS printer. Biggest improvement from adding more RAM is that it then allowed previously unprintable files to breeze through without problems.

Geez, with RAM so cheap, why not max the sucker anyhow just for the heck of it?!?

dan k

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I agree with you, danke, but

I agree with you, danke, but he is a tech at EE with a lot of points and he is the top tech for answering questions at EE in the printer section. I was actually doubting myself since he appears to have much more experience.

Its not a matter of maxing it out since ram is so cheap (which i agree with totally) but rather its a matter of princple now. LOL

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eeun's picture
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It's a tough call...I'd say t

It's a tough call...I'd say the 'guru' is closer to being right.

In theory, a printer should only require extra ram to print larger documents & more fonts. RAM shouldn't offer a noticeable speed boost printing a single document, as the printer is either going to store the page as it rips/converts it for printing, or it's not going to print it, and error out with a buffer overflow/insufficient memory message.

Where you get a speed boost is printing multiple pages if you have more memory, as the printer can output a page while still receiving information for the next page (providing the particular printer is capable of doing both at the same time)

On another area, though, I've owned an HP 4M, and pushed the memory up to 24MB. I found it to be an abysmally slow printer compared to my 16/600 with the same RAM, but neither slowed down my beige G3 once the documents were in the spool and punping to the printer in the background. The 16/600's faster risc processor is what speeds up the printing in this case.

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davintosh's picture
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Listen to the guru...

He is correct.

But it sounds like one of the user's main concerns is that the computer slows down while the pdf is printing. That's the result of Acrobat spooling the print file to disk then feeding that print file out to the printer over the network. Adding more memory to the printer isn't going to help that a bit. A 3MB pdf file is relatively huge, and when printing it results in a spooled file several times that size.

Unless there is a reason to keep the images in the pdf at full size -- there usually isn't, especially if the images are scaled down in the origiating application -- the Distiller settings ought to be adjusted to drop the resolution of the images down to a more reasonable size. If the pdf will only be used for laser output the final image resolution should be no higher than 150dpi. If it's intended for high-resolution printing -- offset printing -- it should be no higher than 300dpi.

The one thing that would make the most difference in speeding things up is giving the printer only what it needs for producing the image, and the best place for that to happen is during the creation of the pdf. If the pdf is overweight, the postscript will also be, only more so, and getting it to the printer will go very slowly. Even if the document is going to be used for hi-res printing, it sometimes makes sense to make a second document at a lower resolution for laser printing, and even lower resolution for online viewing.

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dankephoto's picture
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Maybe I'm biased . . .

because I tend to print docs with lots of large tiffs and epses and that sort of thing all of which sorely tax any printer with limited memory. Sure, most peeps can get by printing text docs with the base amount of ram, but once you start pushing larger files into the RIP it can quickly choke.

As I wrote above, modern printers play all sorts tricks to work within limited amounts of RAM, but I'll continue to argue that in all cases they'll work better and faster with more RAM than with less.

Regarding print speed there's other factors involved as others have noted. I was just addressing the original question about RAM.

dan k

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tmtomh's picture
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More RAM Helps, regardless of the reason

For some time I used a trash-picked LaserJet IIIp (gotta love CUPS printing in OS X!), It came with 1MB RAM. Any word processing document longer than three pages would cause it to choke (not print at all), or to print only the first few pages, usually with no toner put down after the first half of the third page. Single-page PDFs with graphics in them were a crap-shoot in terms of whether the printer would be able to image the entire page before printing onto the page.

I found a 2MB upgrade card on eBay, thereby tripling its RAM. The aforementioned PDFs printed with no problem. Word processing files up to about 8 pages would print fine. (These were MS Word files; I'm guessing pure plain-text files could be of longer length and still print out fine.)

The speed of the printer remained the same in terms of time to first page out, and in terms of average PPM. It did seem to me that pages containing graphics did start to print faster when I had more RAM, but I can't swear to it.

Finally, I retired the IIIp because I trash-picked a LaserJet 1100. It had 2MB RAM, which I quickly upgraded to 10MB via a $5 used module. Again, the capacity of the printer has improved tremendously, even if the speed hasn't.

I guess I just don't see the point in discussing whether RAM increases speed. That's so irrelevant to the contribution RAM makes to a printer's usability. One choked job because of insufficient RAM and you lose lots of time, regardless of how fast or slow the printer's engine is.

My $.02.

Matt

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Thanks for everyones comments

Thanks for everyones comments.

I actaully have learned something new!

Well then looking at the customer's situation, what do you guys recommend? How much memory should he have in the 5M printer to make a happy camper? I still really don't think that 6 megs is going to cut it with 3 meg pdf documents.

So what do you guys recommend for a good memory size for this printer.

And what else might be choking the customer's pdf printing on his beige g3 with os 8.6/9? He is currently printing to an HP 4M with 4 megs of memory.

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davintosh's picture
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I guess the bottom line is th

I guess the bottom line is that there are times when adding memory to a printer will help, but only in those cases where the printer is choking on the docs you're sending it. Those cases are easy to spot because the printer will simply not print the doc you send to it.

On the other hand, if the docs you're sending to a printer will print, but it takes a long time to get the printing progress bar off the screen and paper out of the printer, loading the printer up with RAM isn't going to change that. A better approach is to streamline the document you're printing to reduce the amount of data that has to be fed to the printer.

In my experience (tech support in the graphics department of a $75M printing company) spending a little time up front reducing file sizes and reducing images to the minimum resolution that's needed makes the biggest difference in getting pages printed.

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dankephoto's picture
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print speed from PS printers

Items affecting print speed, in a rough order of importance (IMHO):

size and nature of print file
connection speed between user and printer
printer's specs, incl. amount of available printer RAM
user's computer's specs, including available scratch space (usually spare space on startup volume)

Since there's lots of variables which affect which how long a file takes to print, which factors are more important depend largely upon the nature of the print job. However, I found the biggest overall (print jobs large and small) improvements came when switching from a LocalTalk connection to ethernet.

Obviously, the bigger the file, the more important the connection speed. Laughing out loud Of course, that applies to all parts of the chain from print button to outtray, generally more resources = faster/and/or/non-choking printing.

dan k

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