This is a guide to upgrading and/or installing memory. There seems to be a lot of confusion, so I'm posting just about everything you'll need to know.
Determining what type of memory you need:
This can be done three ways. First would of course be take out the stick and look for a sticker with all the information listed on it. Almost all sticks have at the bare minimum a serial number which you can look up using google.com. The second would be using manufacturer resources. Looking up what the specifications are using the manual, looking up the information on the manufacturer's website, or finding a listing perhaps on a sticker that's on the outside of the computer case. The third would be www.crucial.com, but you need to know what motherboard you are using, which you can look up using the aforementioned manufacturer steps. The kinds of things you want to look for are going to be it's clock rate. It will be rated as either PC#### or DDR###(# = number). IE PC3200 = DDR400 = 400MHz clock rate. Here's a list of memory clock rates and their equivalencies:
PC RATING DDR RATING CLOCK RATE
DDR2 (Double Data Rate Revision 2)
PC2-10000 = DDR2-1250 = 1250MHz
PC2-9200 = DDR2-1150 = 1150MHz
PC2-9136 = DDR2-1142 = 1142MHz
PC2-8888 = DDR2-1111 = 1111MHz
PC2-8800 = DDR2-1100 = 1100MHz
PC2-8500 = DDR2-1066 = 1066MHz
PC2-8000 = DDR2-1000 = 1000MHz
PC2-7200 = DDR2-900 = 900MHz
PC2-6400 = DDR2-800 = 800MHz
PC2-6000 = DDR2-750 = 750MHz
PC2-5400 = DDR2-675 = 675MHz*
PC2-5400 = DDR2-667 = 667MHz*
PC2-5300 = DDR2-667 = 667MHz*
PC2-4300 = DDR2-533 = 533MHz*
PC2-4200 = DDR2-533 = 533MHz*
PC2-3200 = DDR2-400 = 400MHz
*PC number varies based upon manufacturer labeling
PC RATING DDR RATING CLOCK RATE
DDR (Double Data Rate)
PC-4400 = DDR-550 = 550MHz
PC-4000 = DDR-500 = 500MHz
PC-3500 = DDR-433 = 433MHz
PC-3200 = DDR-400 = 400MHz
PC-2700 = DDR-333 = 333MHz
PC-2100 = DDR-266 = 266MHz
SDRAM (Plain)
PC RATING CLOCK RATE
PC133 = 133MHz
PC100 = 100MHz
PC66 = 66MHz (very old)
The next thing is its timing. Don't worry a terrible amount if you can't find this. The rating should come as #-#-#-#-#T (IE 2-3-3-5-1T) Here's a brief rundown of what these numbers are:
2 = CAS Latency (Column Address Strobe)
3 = tRCD (RAS or CAS Delay)
3 = tRPD (RAS Precharge)
5 = tRAS (Number of clock cycles between bank active command and the issuance of a precharge command)
1T = Command Rate (Per row activate command)
Most of this terminology will be very foreign I posted this for people who had questions about memory latencies. Most RAM will configure to slower timings for different boards, but check the RAM manufacturer website before making any purchasing decisions as they will have documentation on known problems, as will the motherboard manufacturer. Next I will describe memory setup.
After you have made sure all of the specs are correct, and you have chosen the amount of memory you wish to upgrade, you need to know how many slots on your motherboard you have to upgrade with, and what the maximum memory is for each slot. Again, you should either check with your motherboard manufacturer if you bought the motherboard separately, or you should check with the computers manufacturer to find out these 2 things. Once you have determined these, go ahead and install the memory.
Additionally there have been questions about Dual Channel capable motherboards. While you can use 2 different manufacturer's (with the exact same specifications) it is going to be easier (and cheaper) to just get a set from one manufacturer. I will describe setups that are usable with various slots on different dual channel boards.
Setup #1:
[============Dual Channel 1 Slot 1============]
[============Dual Channel 1 Slot 2============]
[============Channel 2 DIMM===============]
If you wish to operate without Dual channel memory, you MUST only use Channel 1 Slot 1 and Channel 2, with nothing in Channel 1 Slot 2. You can operate with both Dual Channel, and a DIMM in Channel 2 or just Dual Channel, but only when using Dual Channel should you ever put a DIMM in slot 2.
Setup #2:
[============Dual Channel 1 Slot 1============]
[============Dual Channel 1 Slot 2============]
[============Dual Channel 2 Slot 1============]
[============Dual Channel 2 Slot 2============]
To be able to operate without dual channel here, you can only place DIMMs in Channel 1 Slot 1 and Channel 2 Slot 2. To use any of the other slots, you need to use Dual Channel memory in that channel. Additionally, if you want Dual Channel and 1 separate DIMM, make sure you use Channel 2 Slot 1 as the additional, with Channel 1 in Dual Channel mode.
I hope this answered most, if not all of your questions regarding memory. Thanks and have fun! :lol:
(PS Sticky appreciated here as well thanks! :lol:)
