Installing more printer memory offers many benefits,  including:

• Increased speed on PC
• Faster printing
• Print larger files
• Allow for application processing to run faster
• Increased overall productivity

Try high speed, high performance memory for HP Printers

from www.memorystock.com
Memory Upgrade Specifications

HP 128MB Memory Upgrades for Printers -       128MB For HP LJ9000 # C9121A-PE         128MB For HP Printer LaserJet 4600 Series # C7850A-PE         128MB HP LaserJet 4100 100PIN DIMM # C9121A-160104-PE         128MB Kit for HP LaserJet 8500 8500N 8500DN # C3913A-HPPR2-PE         128MB Module for HP DesignJet 500 & DesignJet 800 # C2388A-HPPC0-PE     HP 16MB Memory Upgrades for Printers -       16MB Color LaserJet 8550 HP PR Mod # C7843A-HPPRN-PE         16MB For HP Color LaserJet (C3100A) # C3146A-HPPRN-PE         16MB For HP DesignJet 1050C (C6074A) # C6251A-HPPRN-PE         16MB For HP DesignJet 200 220 # D2676A-HPPRN-PE         16MB For HP DesignJet 2500CP 2000CP # C6231A-HPPRN-PE         16MB For HP DesignJet 650C C2859B/PSC3792A # D2297A-HPPRN-PE         16MB For HP LaserJet 4000 4000T # C4142A-HPPR1-PE         16MB For HP LaserJet 4000 4000T 400 EDO DIMM # C4137A-HPPRN-PE     HP 32MB Memory Upgrades for Printers -       32MB For HP Color LaserJet 5 # C2298A-HPPR1-PE         32MB For HP Color LaserJet 8550N 8550DN 8550MFP # C7845A-HPPRN-PE         32MB For HP Copyjet C3817A M C3819A # C2298A-HPPR2-PE         32MB For HP DesignJet 1050C (C6074A) # C6252A-HPPRN-PE         32MB For HP DesignJet 2500CP 2000CP # C6232A-HPPRN-PE         32MB For HP Dskjet 1600C/1600CM/1600CN # D3578A-HPPRN-PE         32MB For HP LaserJet 4000 4000T # C4143A-HPP-1-PE         32MB Kit For HP DeskJet 2500C # D3648B-HPPC0-PE     HP 4MB Memory Upgrades for Printers -       4MB EDO For HP LaserJet 1100 Series 1100/SE/XI # C4135A-HPPRN-PE         4MB For HP Color LaserJet (C3100A) # C3132A-HPPRN-PE         4MB For HP LaserJet 5L 5L-FS # C3148A-HPPR1-PE         4MB For HP Printer LaserJet II P # HP33477B-PE     HP 64MB Memory Upgrades for Printers -       64MB For HP DesignJet 1050C (C6074A) # C6258A-HPPRN-PE         64MB For HP LaserJet 4000 4000T # C3913A-HPPR1-PE         64MB For HP Printer Color LaserJet 8550 # C7846A-HPPRN-PE         64MB HP DesignJet 5000 LaserJet 4550 # C7848A-HPPRN-PE         64MB HP PR DesignJet 500 Series 500PS 24/42 # C2387A-PE         64MB Kit for HP DeskJet 2500C # D4543A-HPPC1-PE         64MB Kit for HP LaserJet 8500 8500N 8500DN # C4143A-HPP-2-PE     HP 8MB Memory Upgrades for Printers -       8MB For HP Color LaserJet (C3100A) # C3133A-HPPRN-PE         8MB For HP Color LaserJet (C3100A) # C3133A-HPPRN-PE         8MB For HP DesignJet 200 220 # C2066A-HPPRN-PE         8MB For HP LaserJet 4000 4000T # C4141A-HPPR1-PE         8MB For HP LaserJet 4000 Series LaserJet 4000 5000 8100 # C4136A-HPPRN-PE         8MB For HP LaserJet 5L 5L-FS # C3149A-HPPRN-PE

You will find amazingly low rates on quality HP Printer memory, with fast shipping and guarantees!
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Select your right HP Printer Memory

What are SIMMs?

Many HP printers take 72-pin SIMMs ("PS/2" SIMMs).

What does that mean?

This depends on the kind of printer you have. Some need SIMMs with parity, some can take SIMMs with or without parity (SIMMs w/o parity are a lot cheaper).

HP LaserJet IIISi, 4(M), 4Si(MX), DJ 1200C(/PS), PJ XL300(/PS), DnJ A/B, DnJ 200/220 and DnJ 600 printers:
 

• The SIMM needs parity. Real parity, not "fake" (computed) parity.
   
• The SIMM needs to be FPM, 70ns or faster. EDO memory will work in some printers, but not all.
   
• The Presence Detect pads need to be connected correctly.
   
• N.B.: HP's part numbers for parity SIMMs are C2065A and C2066A (4MB and 8MB respectively).
   

Almost all other HP models that take SIMM:
 

• The SIMM does not need parity.
   
• The SIMM needs to be FPM, 70ns or faster. EDO memory will work in some printers, but not all.
   
• The Presence Detect pads need to be connected correctly.
   
• N.B.: HP's part numbers for non-parity SIMMs are C3132A, C3133A and C3146A (4MB, 8MB and 16MB respectively). There seem to be several part numbers for 32MB SIMM, I have seen D2298A, D3578A and KTH-NPVEC/32.
   

Memory types?

FPM stands for "Fast Page Memory". This is an old memory type, usually found at 70ns or 80ns. Anything 60ns or faster stands a good chance of being EDO, though there is 60ns FPM memory. You cannot tell FPM and EDO memory apart by just looking at the module; though you can look up the part number of the memory chips used and see whether they are FPM or EDO memory.

To tell memory with parity apart from memory without parity, simply count the number of memory chips on the module. If it has 9 or 18 memory chips, all alike, it has parity. If it has 4 or 8 or 16 memory chips, all alike, it does not have parity.
If your module has 8/16 (unlikely to be 4) memory chips and then another 1/2 chips that are not memory (but probably "in line" with the memory chips, like this: MMMMcMMMM), then it most likely has computed parity rather than real parity and will not work in a printer that needs parity.
What looks like a parity module might also be ECC, though; so be sure what you are getting before you get it.

Regarding EDO SIMMs: Whether this works depends on your printer model. Seriously though, we have had reports of successful use, and reports of unsuccessful use.
The memory controller has to support EDO if there is to be any chance of it working. With older printer models, that is probably not the case.
Mixing FPM and EDO is discouraged, because it is not stable at what was considered high memory access speed in those days. However, since HP says "80ns or slower", we do not necessarily see a problem in using EDO, as long as it works: Even though the built-in memory will be FPM, and thus you are mixing.

ECC memory is error-correcting memory and will never work in a HP printer, though it will physically fit.

Regarding speed: 70ns or faster means you can take a 60ns SIMM, encode it as 70ns, and it will work. We have successfully done this. HP actually quotes 80ns, or "80ns or slower", but we like to be very conservative about this kind of thing. SIMMs you buy nowadays will be 60ns, anyway.

Presence Detect pads?

Right. Pads (or pins, if you so will) 67 to 70 on a 72-pin SIMM encode the size and speed of that SIMM. Each of them can either be open or connected to GND (ground). Look at a SIMM you took out of your PC. Chances are you will see traces running from pads 67 to 70 to empty points where a solder blob or SMD resistor would fit. If the traces run to actual solder blobs or zero ohm SMD resistors, then the SIMM has been encoded already ... it just remains to be found out whether it has been encoded correctly.

PC clones, as a rule, do not use the Presence Detect pads on a SIMM. That's why the pads are (usually) left unsoldered. Furthermore, there is no standard for the encoding of these pads. IBM has their own way, as does HP, as does Dell, as do others.

So the printer recognizes memory just by the pattern on these pads?

Exactly. If all four pads are open (no solder blobs, no resistors), then the printer will not "see" the extra RAM ... it's as if you never put that SIMM in there. Once you put some solder over the right points on the SIMM, you have magically transformed a $39 SIMM into a $150+ HP printer memory expansion.