PC xxxx vs PC2 xxx RAM

[Beer4MeThx]

I purchased a used desktop from an IT surplus auction and I am wanting to add some more RAM. It is a HP 4400 workstation. I have been doing some research and have confused myself.

Looking on tigerdirect.com I see DDR2 ram listed as both PC xxxx and PC2 xxxx, but when researching if either will work for my machine I have came across other posts saying PC xxxx memory is DDR whereas PC2 xxxx is DDR2. Why would tigerdirect list both PC and PC2 as DDR2 if this is the case?

From HP specs this is the RAM shipped with machine: DDR-2 667 MHz ECC unbuffered. From what I have read I am afraid to buy PC xxxx if it is not DDR2. Thanks for any help.

 

[tracerbullet]

Could just be an error on TD's part. I could be wrong of course but I remember the DDR# and the PC# aligning. That is to say PC2 XXXX is DDR2, PC3 is DDR3, etc.

The socket size should tell you for sure. If you have DDR2 now, you will want more DDR2 in the future. Won't be able to fit the others.

ECC is a different story, I don't remember ever having success with some of each. *I think* You'll have to have more ECC if you just add RAM or replace it all if you don't. Check on that to be sure you don't end up with anything incompatible.

 

[Harvey]

DDR and DDR2 (PC xxxx and PC2 xxxx) are not pin compatible so you can't use both in the same sockets. During the change over, some manufacturers included separate sockets that allowed you to use one OR the other, but not both. You may also be finding both DDR and DDR2 (PC xxxx and PC2 xxxx) listed for this basic model group because HP may have produced machines with this generic 4400 series model number that used one or the other.

If your machine has DDR2, that's what you should buy. A little more info that may help:

From the general description, I'd guess the machine probably came with XP (32 bit) installed. The 32 bit OS can only use 3+ GB of RAM. However, if the machine also includes onboard video (not a plug in AGP or PCI video card), and if your machine can recognize 4 GB of RAM (2 x 2GB sticks if you have only two slots) it will use the RAM above 3+ GB for the video instead of subtracting the RAM it uses from the RAM pool available to Windows.

I've had good success with this in many HP machines, but every machine is different so you'll have to test it. If it starts to boot with 4GB installed, go into the CMOS, and check the amount of installed RAM. If it shows all of it, you win. When you check it in Windows (My Computer > Properties), it will show only the 3GB "seen" by the OS.

To be sure which your machine uses, check HP's info, but don't just look for the 4400 series. Check the sticker on the back or side for the exact model number and/or part number (p/n). If you can't find it on HP's site, check the RAM manufacturers for that exact model and/or search Google for the exact model number + memory.

Hope that helps.

 

[Beer4MeThx]

Thanks for the responses. I pulled some old RAM from another machine and it was only DDR so I did not install it.

So Harvey you are saying it would be no use to buy more than 3GB if I am using a video card because the OS won't recognize it (assuming the OS is not 64 bit)? It is running XP Pro and I would also assume it's the 32 bit version but I will check when I get home to be sure.

I believe my model is RB387UA. These specs match my machines:
2.13 GHz
2 x 1GB DDR2

 

[nenforcer]

PC2-5300 is DDR2-667 MHz while PC2-6400 is DDR2-800MHz. The former is much more common and is typically the standard while the latter may be considered overclocked in a workstation / server motherboard.

 

[DaveVandorAmon]

Your box as an HP 4400 workstation is probably an xw4400 workstation, if it is a workstation and not an HP desktop line.

Compatibility is determined by the Mfg as 4 slots, max 2GB per slot, DDR2-667 ECC Unbuffered. Dual-channel. Pairs must be matched in size and speed. 8GB max, limited only by 32-bit OS. All DIMMs greater than 1GB must be ECC/Unbuffered.

Crucial configuration: http://www.crucial.com/store/listpar...xw4400&Cat=RAM

You could potentially buy PowerEdge / Precision compatible ram in the used market. A 4x2GB kit would range from $80 - $125 - definitely try to buy all 4 sticks from the same source and that they match.

 

[dave_the_nerd]

I commonly see DDR2 and DDR3 labelled as "PCxxxx" by stores, even though the memory itself will say PC2/3xxxx on the package.

Example (Note that the category header is PC6400, and they use both PC and PC2 interchangeably in the item descriptions.)

Because the "xxxx" numbers are typically much higher than the corresponding number for actual (old fashioned) DDR, there's little doubt what you're getting. (There's no such thing as PC6400 or PC10600 DDR1.)

 

[Harvey]

So Harvey you are saying it would be no use to buy more than 3GB if I am using a video card because the OS won't recognize it (assuming the OS is not 64 bit)? It is running XP Pro and I would also assume it's the 32 bit version but I will check when I get home to be sure.

Unless the installation disk says it's a 64 bit version of XP, Windows XP Pro and Home are 32 bit versions which are limited to recognizing just a little over 3 GB of RAM. I have installed 4 GB in my own HP laptop with XP Pro, which obviously has onboard video. Windows shows 3 GB of memory. The video system uses the RAM above that. I have done the same on other laptops and desktops, but I have encountered some that don't work because the system doesn't recognize 2GB sticks.

I believe my model is RB387UA. These specs match my machines:
2.13 GHz
2 x 1GB DDR2

HP's product page for your machine confirms the memory info posted by DaveVandorAmon and more. Your specific model number probably indicates the particular processor and RAM combination included with your machine.

The machine can use 32 or 64 bit versions of XP and Vista and Red Hat Linux. The linked page has a link to the drivers you'll need for your OS.