RAM Finder

There are so many different types of RAM, and to the untrained eye these varying memory chips may look indistinguishable from one another. This page is designed to help you figure out the type of RAM your computer uses. The easiest way to determine your RAM requirements is to use the Crucial Memory Scanner tool.

Visit the Crucial Memory Scanner homepage here: Crucial Memory Advisor Tool

1. How many RAM slots do you have altogether?
2. How many RAM slots are free?
3. What is the maximum amount of RAM the motherboard will address?
4. What is the maximum size of each memory module you can fit into a slot?
5. Is dual channelling supported?
   
   

Picture	Type of RAM	PC Rating	Speed	Peak Throughput
	SDRAM	PC-100	100 MHz	800 MB/sec
	SDRAM	PC-133	133 MHz	1100 MB/sec
	RIMM	PC-800	400 MHz	1600 MB/sec
	RIMM	PC-1066	533 MHz	2100 MB/sec
	DDR	PC-1600	200 MHz	1600 MB/sec
	DDR	PC-2100	266 MHz	2100 MB/sec
	DDR	PC-2700	333 MHz	2700 MB/sec
	DDR	PC-3200	400 MHz	3200 MB/sec
	DDR2	PC2-3200	400 MHz	3200 MB/sec
	DDR2	PC2-4200	533 MHz	4200 MB/sec
	DDR2	PC2-5300	667 MHz	5300 MB/sec
	DDR2	PC2-6400	800 MHz	6400 MB/sec
	DDR3	PC3-8500	1066 MHz	8500 MB/sec
	DDR3	PC3-10600	1333 MHz	10600 MB/sec
	DDR3	PC3-12800	1600 MHz	12800 MB/sec
	DDR3	PC3-15000	1866 MHz	15000 MB/sec
	DDR3	PC3-16000	2000 MHz	16000 MB/sec

• The first number (2) is CL, the CAS Latency. This value has the most effect on system performance. It is usually 2, 2.5 or 3 for DDR memory.


• The second number (3) is TRCD, the RAS to CAS delay. Not as critical as CL, it is usually 2,3 or 4 for DDR memory.


• The third number (2) is TRP, the RAS Precharge delay. This value has similar effects to TRCD.


• The fourth number (6) is TRAS, the Active to Precharge delay. This value affects stability more than performance. Typically between 5 and 8 for DDR memory.


• The last figure (1T) is the Command Rate and is often omitted, as it is almost always 1T. For slow RAM it would be 2T. Strangely some overclockers get very good results by deliberately setting the Command Rate to 2T even with low latency RAM as it allows them more flexibility when tweaking the other latencies and bus speeds.

Note that the numbers are valid only for the rated clock speed and will also be quite different for different types of RAM.