Hi, I want to upgrade my PC from 512Mb DDR 333Mhz (1 Module) to 1Gb DDR 333Mhz (1 Module). I found myself pretty confused when I started to check prices and brands of memory. I found some cheap memory modules on Ebay. Around 120USD for "Spectek" memory chip. But it's Non-ECC, Non-Registered, Non-Buffered, Non-Parity. What does those all "non" means? There are also more expensive modules from Micron or Elixir, but also non ECC and non registered. And registered modules for even higher price but mainly only 233Mhz DDR. Well my 512Mb module is non ECC and non registered also what I found out today, but untill this time I had no problems with it...
What kind of memory would u suggest me to buy?
My PC is runing on P4 2.4Ghz CPU and Intel D845GEBV2 Motherboard with 2 DDR 233/333Mhz slots.
ECC is good and damn near essential (ECC = error correcting code, i.e., SELF-error correcting :P)
Parity is a technique by which simple errors are caught and corrected (partity is synonomous with ECC)
As for registered memory, this just means that there is an additional chip on the module (typically mounted sideways) and boosts the signals running to and from the module (kinda like a filter); it also does some retiming as needed. This additional 'filtering' takes one clockcycle so if ur crazy for clock-cycle savings then this is not your option. Registered memory is important when it comes to servers setups and the like.
Buffered is synomous with registered.
For most people ECC, non-buffered memory is the way to go. (Praetor also reccommends Corsair memory :P)
I always get a name brand memory, I wouldn't take a chance on Spectek myself. I usually get Crucial, but Corsair is equally good.
http://www.crucial.com/ Crucial has a memory selector on their site, just put in your computer or motherboard info and they tell you what memory is compatbile.
Thank you booth for information and help. I think I will look for some name brand memory. Corsair, Crucial or maybe Kingston. Possibly It's a good idea to get two similar 512mb chips as I have two slots on my motherboards and I do not think that I will need to install more than 1Gb on this system. What relates to clock-cycle savings I prefer quality not speed. So if it will be possibly I'll get registered memory.
If you are lookin for quality (which shouldnt be a big issue for 90% of people since generic ram is more than sufficient), check with your mobo manufacturer to see what brands & models they reccomend.
Most mobo manufacturers will CLEARLY specify what types of memory modules are supported by their memory controllers / BIOS - so there is not much choice there (and some motherboards are less forgiving and basically force you into buying specific memory type)
Parity is an older 'error detection' only technology - it can only inform system about single bit error. It will do nothing to correct it (at least not by itself). Parity is NOT synonymous with ECC. Obsolete by today?s standards.
ECC is a newer 'error detection and correction' - it can correct single bit errors by itself. Not all motherboards support it (actually most non-server systems do not support it).
Parity memory was widely used prior to 1995, and it disappeared with advent of EDO memory (and need for inexpensive memory in general).
ECC is widely used with server mobos as those require prolonged error-free operation. (Same is true for registered / buffered memory).
For most users both of those are not necessary. If your memory develops errors your system/software will quite likely crash (and you will need to reboot - which clears the error). If you are getting many errors that can be attributed to memory - you might have either substandard (or bad) memory stick (can be sometimes tested with a software utility), aging memory stick (those tiny capacitors tend to deteriorate), or serious problems with cooling (especially over-clocking memory heat sinks / spreaders are essential).
However, for users with large amounts of memory (several gigabytes) ESS will be beneficial (as chance of errors increase with sheer amount of memory cells). The same way getting registered modules (type of buffering; usually for multiple stick setups and setups over 1GB; increases reliability of transfers but slows down the system slightly), matching pair modules and (in general) good quality modules usually helps.
For general computing non-registered, non-buffered, non-ECC memory will be most popular (and adequate).
In my experience going for quality manufacturer is important, however as important are specs for refresh and read timing - and that will also contribute to error free operation.
Quote:Parity is an older 'error detection' only technology - it can only inform system about single bit error. It will do nothing to correct it (at least not by itself). Parity is NOT synonymous with ECC. Obsolete by today?s standards.
Actually parity can handle an odd number of errors :-) Furthermore, yes i know Parity is not the same as ECC however on any type of RAM that you can find today on motherboards you can find today -- the partity designation is effectively the same since most of such mobos are able to handle such corrections.
But we are not talking about memory build onto mobos... We are talking about memory sticks. And just because somebody uses the term 'parity' incorrectly... Lets call a spade a spade...
