Dell's documentation for the Dimension 4550 incorrectly states that the maximum memory is 1GB. Most websites and memory configurators also state this maximum. However, this is only the maximum memory TESTED for the Intel 845PE chipset (the chipset used by the Dimension 4550) around the time it came out. According to Intel, the actual maximum memory for the chipset is 2GB.
Dimension 4550 owners on Dell's forums and the web in general have reported installing and operating with 2GB without problems, although not all SDRAMs are compatible. All this means the Dimension 4550 supports SDRAMs up to 1GB in each of it's two memory sockets for a total of 2GB of memory. However, according to Intel, the 1GB SDRAM must meet certain specifications.
When Dell came out with the Dimension 4550, Intel (with their 845PE chipset motherboards) was not able to TEST the Intel 845PE chipset using 1GB DDR SDRAM memory. While Intel's documentation explicitly states that it is supported, only 1GB SDRAMs with an organization of x8 are specified to work. (For SDRAMs 512MB or less, both x16 and x8 organizations will work.)
Locating compatible 1GB memory:
First, make sure your BIOS is updated to A08. The BIOS version is shown when booting. You can get the BIOS update from Dell's Support download page for the Dimension 4550.
To locate compatible 1GB SDRAM for the Dimension 4550 that meet Intel's specifications, one need only find compatible memory for Intel's D845PESV motherboard, which uses the same chipset as the Dimension 4550. Specifications for Intel's D845PESV Motherboard are: Intel 845PE chipset, 478 CPU Socket, 400/533MHz FSB, ATX form factor.
Any memory manufacturer or memory retailer will tell you what memory is compatible with Intel's D845PESV motherboard. This is easy to do with online memory configurators/locators. Simply enter your system as a desktop or motherboard, maker Intel, Intel motherboard, and model D845PESV. If your Dimension 4550 is a 533MHz FSB (Front Side Bus) use at least the PC2700 memory returned by the configurator (don't use PC2100). For 400MHz FSB use PC2100 memory (faster memory should also work). (If your CPU is 2.2GHz or less you're running a 400MHz FSB, if it's higher you're running a 533MHz FSB.)
Compatible 1GB memory:
Listed below is PC3200 1GB SDRAM memory for Dimension 4550 that should work with either 533 or 400MHz FSB. Note that PC3200 memory supports a faster clock speed than needed, but seems to be more readily available than PC2700 or PC2100 memory at about the same price.
PC2700 1GB SDRAM memory for Dimension 4550 with a 533MHz FSB (these should also work with a 400MHz FSB):
PC2100 1GB SDRAM memory for Dimension 4550 with a 400MHz FSB:
Intel Desktop Board D845PESV - http://www.intel.com/design/motherbd/sv/Intel 845GE/845PE Chipset Datasheet - http://www.intel.com/assets/pdf/datasheet/251924.pdf
Dell Dimension 4550 - Technical Specifications - http://support.dell.com/support/edocs/systems/dim4550/specs.htm
Newegg.com's memory configurator for the Intel D845PESV motherboard, 1GB - http://www.newegg.com/Product/ProductList.aspx?Submit=ENE&N=1052307858&Configurator=MemoryConfigurator&CFG=CFG003D845PESV&name=1GB
Earlier I had upgraded my Dimension 4550 by adding 512Mb (to the original 256Mb), and then I discovered this article, quite by accident. I upgraded the BIOS to A08 (easy peasy), bought 2 Kingston 1Gb memory modules, installed them and I am now happily using 2Gb of memory on the old workhorse. Couldn't have been easier.
I upgraded my 4550 Bios to A08 as well, purchased 2 - 1 GIG PC3200 SDRAM DDR400 memory cards, installed them and got no reaction. Computer would not boot. These sticks show that they are compatable in this process and they clearly are not. I reinstalled my 2 -512 memory sticks and it went back to working normally at 1 GIG, just slow. I would caution those wanting to do the same that this theory doesn't always work, as I have proven.
I just want to report back of my success after reading this thread and installing a new 1GB PC2700 CL2.5 stick.
Dimension 4550 / FSB 533MHz; max memory frequency 333MHz;
1GB DDR PC3200 CL3 should work identical in such systems.
Be cautious that the high density DDR PC2700/PC3200 probably will not work for this model. And definitely don't use DDR2.
The high density DDR is much more cheaper, you can get about $12-20 for 1GB on eBay or after-rebate at Fry's.
The low density DDR cost about $35 for 1GB currently.
I would have by 2x 1GB, but the low density 1GB DDR PC2700/3200 is relatively expensive and I decided not to overspend for this now kids' computer.
I bought the system new with 128MB PC2100 /266MHz shipped. Immediately, I throw the 128MB/PC2100 out and put in one 512MB/PC2700 which was around beginning of 2003. As XP grew fatter with service packs and patches along the way, I added second 512MB/PC2700 probably around 2005. If I knew that the socket actually takes 1GB, I might have bought 1GB stick back then.
Both of my earlier 512MB modules are KVR333X64C25/512;
so I bought the 1GB from the same design family KVR333X64C25/1G
Again, I believe the key for success is probably to get low density DDR module.
#1- All I did was buy two new 1GB,DDR PC3200 (PNY) a total of 2GB and installed them. I did not change anything at all (BIOS still at A00) factory set from Dell, and it works like a champ. #-2- I also am going to install a P4 3.06 533FSB 478pin 512 Cache CPU (SL6PG) and all I've read was then to change BIOS to A08 for the HT. Will the BIOS setting for the SL6PG be correct set at A08 ? Thanks, Advenger
I want to report my success after reading this thread and installing two Kingston 1GB PC2700 CL2.5 sticks, not LOW DENSITY I dont think @ KVR333 / 1GR.
This is a Dimension 4550 / FSB 533MHz; max memory frequency 333MHz;
Previously had 1GB DDR PC3200 by using two Kingston 512MB KVR400 / 512. Came stock with 256MB!? What a joke!.
These were pretty cheap, $25 each for 1GB at Fry's.
No upgrade to A08 on BIOS. Has A05. Popped the sticks in and worked just fine. Booted and Recognized right away.
People, this machine is a workhorse. (P4 2.53 Ghz CPU) My box is now over 6 yrs old, and it still amazes me. Example: GEForce 420 mX card is just outstanding for it's class back then. Bought a 24" Samsung monitor with native 1900x 1280 recently, and the card runs this monitor great with a ton of settings. Not a huge gamer, but the 4550 still rocks, and now even better with the 2GB of RAM. I believe this box had to be one of Dell' s best in show for it's time. Just wipe your hard drive periodically to be fresh, or maintain well, add a external hard drive and you'll be amazed at this relic, or at least I have.
The following memory did NOT work for me in the 4550: (Dimension 4550 / FSB 533MHz)
G.SKILL Value 1GB 184-Pin DDR SDRAM DDR 400 (PC 3200) Desktop Memory Model F1-3200PHU1-1GBNT
Just installed 2 x 1GB Ram in Dell 4550 successfully - everything working fine.
Kingston Value RAM 1GB DIMM 184-pin DDR 333MHz - Ref: KVR333X64C25 1G
Successfully installed 2 x 1GB Ram in Dell 4550 - everything working great.
Running BIOS A08
Pentium(R) 4 CPU 2.53GHz 533FSB
Left the BIOS at the A05 factory setting from Dell.
Installed 2 X 1GB Kingston Value Ram 184-Pin DDR SDRAM DDR 400 (PC 3200)
I'm running 2GB of memory without any BIOS update whatsoever.
I have a Dimension 4550 (533MHz FSB) System which had just 512MB of original ram and wanted to upgrade to larger memory. Stumbled on this forum via google and found it very useful, thanks for all the comments. I foloed the help above and bought 1GB of PC2700 and was able to upgrade successfully and so now have total 1.5GB of memory working very happily and computer has really speeded up (although I am not a gamer just regular user).
I bought Crucial Part No. CT1161311 1GB 184-PIN UNBUFF DIM 128MX64 DDR PC2700. I bought it direct from the crucial website as the said "Compatible memory upgrade for your computer - Guaranteed" which kind of reassured a non-techie like me. Especially as some websites were showing that max RAM is 1GB for the 4550 but the Crucial site was showing 2GB.
I ran the www.crucial.com/systemscanner and it was able to identify exactly the memory I had, how much I could add, the slots, etc and showed clearly that I needed PC2700 or PC3200. The prices were the same on the website so I just bought the PC2700 to be compatible with the 512MB I already had which was also PC2700.
Dell website had a similar system helpful analysis tool which I also ran but it kept freezing on me for some reason.
I have BIOS A03 and I did not change it. Everything seems to be running fine.
This sure beats buying a new computer. Thanks again to everyone for the earlier comments, really helped me out.
I bought my Dimension 4550 seven years ago, upgraded RAM to 2GB, upgraded CPU to P4 3.06G, BIOS A08, power supply Dell Silencer410, X-FI sound card, and run ATI Sapphire 3850 video card, and the computer runs great. Probably will upgrade to Windows 7 soon, not bad for an old work horse.