DDR2 vs. DDR3 explained: Info Inside...

[BeepBeep2]

Now, I'm pretty sure that most Computer geeks and even new guys emerging into the tech world would want the best "bang for the buck". Maybe one guy is upgrading his system. Maybe the other is building his first system. And then there is that guy with oodles and oodles of currency in his back pocket that just wants to get the newest thing out there because he can.

Now, what is the difference between DDR2 and DDR3 you ask? Three things set these both apart.
1. Cas Latency,
2. Rated Speed,
3. Voltage.

1. First off, Cas Latency. It's the amount of time in cycles between the signal from the CPU and the data being relayed back. Lets say, CAS 4 DDR2-800. (These are usually labeled "4-4-4-12".) They will be faster than lets say, CAS 5 DDR2-800. (Usually 5-5-5-15 or 5-5-5-18)
When talking about DDR2, the most common Cas Latencies are CAS 4 and Cas 5.

With new and emerging DDR3 on the market, these use slightly slower Cas Latencies to achieve a higher "Rated Speed". These modules usually range between CAS 6 and CAS 9. CAS 6 being fastest, CAS 9 being a tad bit slower. It's the same principle as DDR2.


2. Second, the Rated Speed. It's kind of like a processor. CAS 5 DDR2-1066 will always be faster than CAS 5 DDR2-800. Because it's running faster. But, I'm saying rated speed because DDR2-1066 is actually running at 533 Mhz. DDR means Dual Data Rate, so DDR2-800 is also running at 400 Mhz.
DDR3 has a higher Rated Speed than DDR2, in most cases. DDR2 starts out at 400 Mhz and reaches up to 1200 Mhz. DDR3 starts out at 1066 Mhz and goes all the way to 2000 Mhz. The higher the speed is, the lesser the lifespan of the RAM modules.

My personal reccomendation if choosing value RAM is to go with DDR2-1066 or DDR2-800. It's about the same price as DDR3-1066 and most DDR2 modules have a CAS latency of 5 instead of 7 or 8 like low-end DDR3 sticks.

3. Third, voltage. DDR3 usually stays between 1.5 and 1.8v. DDR2 is usually between 1.8v and 2.2v. For DDR3, anything over 1.8v is considered moderately dangerous. (While some manufacturers market RAM up to 2.0v) For DDR2, anything over 2.2v is also considered moderately dangerous. (Though some kit's are up to 2.3v)

DDR3 also generates less heat, because of the lower working voltage.

You may also have noticed while shopping that both DDR2 and DDR3 have 240 metal pins on the bottom. You can not interchange DDR2 and DDR3. The pin's are arranged in different places, and one will not go into the other's slot.

Yes, I wrote this little article because I was bored. If you guys have anything to add or ask, go ahead and post below.

[AndrewJ]

I have had my Quad running on 4Gb of cheapest single channel just to test for fun, apart from overclocking ( even then I ran 3.4GHz lol ) you just cant tell the difference a few micro seconds here n there,

At stock clocks sims ran no stutter virtually same framerate.
Ran tests OCCT prime everest all passed

My point is if you DONT overclock dont waste too much on ram.
I would rather buy 2 x 2GB of generic then 2 x 1GB of named brand

generic is much more reliable these days and most has lifetime warranty

[AMAjr455]

Thanks... Great Insight!