My computer is a eMachines model C2280. The motherboard is an ECS L7VMM2, with a CPU AMD Athlon XP 2200+ 1.80 GHz. I searched the Internet and the information for the memory is the following: Two 184-pin DDR DIMMs sockets for 2.5V DDR SDRAM (DDR266/DDR200) Maximum: 1GB (Unbuffered Memory)/ 2GB (Buffered Memory). When it says (DDR266/DDR200), do that means that I could use either? What is the meaning of buffered and unbuffered memory? Do I need to install the Ram in pairs (like if I want 1 GB, I have to put two 512 KB memory sticks, or can I put only one 1 GB stick)? I read on other site that most eMachines do not accept high density SDRAM... is it true for this one? When buying Ram, most of the time they are listed as PCxxxx (example: PC2100). What would be that number for this model? Ram also come with or without Error Correction Code (ECC) and Registered or not-Registered. Will those affect compatibility? Which are recommended? Any additional information on memory upgrade for this model is welcome. I know little about computer hardware, so if the explanation are kept simple, I will appreciate it. I will probably buy the RAM via eBay (I think I find it cheaper there), so I want to know what things to look for and what question to ask the seller. Please, recommend any other websites with good deals on SDRAM that you know of.

To get the exact ram that you need and is guaranteed for life go to either Kingston or Crucial. Both companies have a selector that is easy to use to get exactly what your system will use for the best performance. It might cost a few dollars more, but it is worth it compared to getting ripped off at ebay.

If you're in the US & don't mind playing the rebate game, just watch the ads at CompUSA, OfficeMax, BestBuy, etc. There's all sorts of sales going on right now for xmas. I just picked up a stick of PNY 256mb PC2700 for $10 after rebate. 1. "When it says (DDR266/DDR200), do that means that I could use either?" - you need to match it to your CPU. Since you have a 266FSB CPU, you'll wanna get at least DDR266 (PC2100) RAM, but PC2700 or PC3200 should also work due to backwards compatibility. 2. "What is the meaning of buffered and unbuffered memory?" - these will help explain: http://www.ivitex.com/faq1.htm#key def http://www.computer-memory-upgrade-stick.com/memory-modules-101.htm 3. "Do I need to install the Ram in pairs (like if I want 1 GB, I have to put two 512 KB memory sticks, or can I put only one 1 GB stick)?" - look back at what you posted in the beginning & do the math. You have 2 DIMM slots, max 1GB unbuffered (so 2 x 512mb), max 2GB buffered (so 2 x 1GB) 4. "I read on other site that most eMachines do not accept high density SDRAM... is it true for this one?" - NO. If it supports (512mb or more) per DIMM slot, it will accept high density RAM. 5. "When buying Ram, most of the time they are listed as PCxxxx (example: PC2100). What would be that number for this model?" PC1600 = DDR200 at 100mhz PC2100 = DDR266 at 133mhz PC2700 = DDR333 at 166mhz PC3200 = DDR400 at 200mhz 6. "Ram also come with or without Error Correction Code (ECC) and Registered or not-Registered. Will those affect compatibility? Which are recommended?" - I'll pass that one on to here: http://www.computer-memory-upgrade-stick.com/ecc-vs-non-ecc.htm http://www.computer-memory-upgrade-stick.com/memory-modules-101.htm http://techimo.com/forum/t55096.html Asus A7N8X-X 1800+ @8x210mhz 512mb PC3200 Ti4200/8X 128mb WDC 60GB

Thanks for all the info. Check the following link, I think this one will fit my PC... http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=6726706896 but... the voltage in the auction info says 3.3V, but my motherboard says to install 2.5V ones. Is this a crucial matter? Or will the memory still work with the applied voltage?

you need 2.5 volts because if you try 3.3v will be unstable if it posts at all david