Hello cj75409, It is known that some of Dell documents on certain systems show some incorrect information.

I don't know about your system.

You might try going to a memory vendor, such as, Crucial, Kingston, OCZ, and others, and do a memory configurator, and see what those companies show for your system.

I would check several, since you may get different results from different vendors.

Usually, but not always, these configurators are accurate. If they prove not to be, the vendors usually will work with you to get the memory you require.

This has been my experience over the years.

Hope this helps.

cj75409

Go HERE and use their memory Scanner Tool, to find the memory that compatible with your 4550.

Bev.

That's inaccurate.  I'm typing this from a Dimension 4550 with a 533 FSB and 2GB of memory. 

Both 400 and 533 FSB support 1GB memory sticks. 

For compatible memory and details on this issue see http://en.community.dell.com/wikis/desktop/dimension-4550-maximum-memory-2gb-not-1gb.aspx

I agree. I just recently installed two 1GB Kingston memory cards in my 533Mhz 4550 Dimension as per the above recommendation. All went very good.  My system recognized the new memory upgrade immediately to 2GB total ram.

Thanks very much for the info and link as I was wondering the same thing!  I have 1GB presently installed in my 4550 and was wondering if I could go to 2 GB. 

How much memory did you have before you went to 2GB?

Did you notice any performance improvements such as in speed after installing the 2GB?

I have 1GB presently installed in my 4550 and I am thinking about going to 2 GB. 

How much memory did you have before you went to 2GB?

Did you notice any performance improvements such as in speed after installing the 2GB?

I had two (2) 512 Mb cards for a total of 1 Gb memory. I installed two 1 Gb cards for a total of 2 GB memory.

Maybe some speed increase, too hard to tell when things get this fast. But definitely faster when running multiple things at the same time or large applications.

As I mentioned above, my system instantly recognized the increased memory capacity with no problems at all.

I just installed a 1 gb PC3200 Corsair Value Select DDR1 400MHz - VS1GB400C3/EU G ($35 @ Fry's delivered) on my Dell Dimension 4550 (533MHz FSB) Desktop/PC and after some trials and tribulations I'm back up and working. Yes!

I thought I'd add a bit of my sad story to this thread. Thanks by the way for the info posted above, it's been very nice. When I opened my case I didn't notice that I 'unplugged' my hard drive connection. It was still there, hanging in there, but I didn't notice. When I went to reboot I got a message saying new memory found, but I couln't reboot because my hard drive was unplugged. I had the choice of F1 or F2. F1 just took me back to the F1/F2 choice. F2 told me my hard drives were "unknown". I'm not that computer literate so I thought my problems were related to the new memory, so after about 3 hours of forum searches I decided to unplug the hard drives, plug them back in and try rebooting again. Luckily, thank god, when I went to disconnect my secondary hard drive the cable connection to the motherboard fell off, and I thought, 'here's my problem'. With fingers crossed I rebooted with success and now have 1.5 gb of beautiful memory on my beloved 4550. If my ineptness helps someone else then it's been worth it.

I did upgrade my bios to V08 beforehand. I had upgraded one of the memory slots to 512 MB a couple of years ago. This time I replace the other 256 with the 1GB.

How did the BIOS upgrade to V08 go...any problems?  I got the following respose from Dell support when I asked about the need to update the BIOS before installing the additional memory:

Response from Dell support: "Please be advised that if you are not experiencing problems on your computer and are not aware of any additional features in the BIOS you are needed, then you may not need to perform the update. What I suggest is that you try installing the additional memory module and test if the system will function properly. However, if you notice inconsistencies on your system, then I suggest that you update the BIOS version.

my update went perfectly.