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What do they mean when they say 'pc3-10600 vs pc3=8500 or pc3-12600

Last response: in Motherboards
July 14, 2010 4:28:26 AM

Just wondering, as i start shopping for new memory, and know nothing about it...i have been suggested some good memory i think, but i was also, that my core i7 will only recognize something like 1066? i have no idea what that means....ALSO, i read that ill have to go into a BIOS and set speeds? i just want more memory, and for it to work safely, for gaming.
July 14, 2010 5:14:31 AM

There have been roughly three generations of double data rate RAM
for desktop and laptop computers:

DDR, DDR2 and DDR3.

The number following each is usually the effective clock rate:
e.g. DDR2-800 has a raw memory clock rate of 400 MHz
that transmits data twice per tick -- hence the "double data rate".

A second convention has developed, which simply multiplies
that effective clock rate by 8 bytes per tick:
thus, 800 MHz x 8 bytes per tick = 6,400 Megabytes per second.

And, that memory has come to be identified as PC2-6400
where the "2" in "PC2" identifies DDR2.

So, let's switch to DDR3, using the same approach:

PC3-8500 was derived by multiplying 8 by some effective clock rate:
so, just divide 8500 / 8 = 1066 (roughly), or DDR3-1066 e.g.:

PC3-10600 / 8 = DDR3-1333; DDR3-1333 x 8 = PC3-10600
PC3-12800 / 8 = DDR3-1600; DDR3-1600 x 8 = PC3-12800

Notice how the latter specs are exactly TWICE the specs for DDR2-800:
i.e. 800 x 2 = 1600; 6,400 x 2 = 12,800.

Browse around Newegg and search for the strings
"DDR2" and "DDR3" and you'll see plenty of examples
of various raw memory clock rates, identified also by their
"PCx" nomenclature.

I hope this helps.


July 14, 2010 5:23:35 AM

p.s. If you are new to choosing RAM, your motherboard
manufacturer should have published a QVL (Qualified Vendor List)
which itemizes each of the RAM makes and models that have
been tested to run AOK in your motherboard with that CPU.

If that QVL did not come on a "Support CD" with your motherboard,
then it will most probably be found in the printed User Manual, and
it will very likely be found at the manufacturer's website for
that motherboard as well.

This is how ASUS does things.

July 14, 2010 1:35:12 PM

ok so, from what i've read, windows vista 64 and my core i7 920, will only process speed @ this means is should buy ddr3-8500? is that right? or if i put faster stuff, like 10600, it will run @ 1066 just fine? my MOBO is factory dell stuff i think...

i went to and they gave me a list of compatible memory off their website.