I have a Dell Studio XPS 16 (1647) laptop that comes with 4GB stock ram. I'm looking to upgrade to 8GB and while browsing the Dell website and TigerDirect for RAM sticks, they have these offerings:

I read a couple of forums trying to understand why one is PC3 and the other is PC1, and one user posted the following:

There is no such thing as PC1 DDR3 Memory. DDR = PC3

Another said:

pc1-pc2-pc3 is ddr-ddr2-ddr3

It's not uncommon for online stores to post incorrect specs on their offerings. Can anyone explain if the Crucial Stick is actually PC3 (since it's clearly marked as DDR3), or if it's incorrectly marked as DDR3 and it's really just DDR?

1 Answer 1


It's PC3. As long as it's DDR3 and the pin count is correct (it is) you're fine. Tigerdirect just left out the PC3, and kept it at PC.

  • Thanks whardy. So the pin count is a definitive confirmation? Like, DDR and DDR2 having different pin count?
    – silverCORE
    Aug 17, 2011 at 17:39
  • +1: The # after PC, but before the dash, is supposed to be the DDR version (so DDR3 RAM should be marked as PC3-XXXXX). When you look up similar RAM on Crucial's site directly, they label it as "PC3-10600 (1333MHz)", so it's just TigerDirect (or more likely their suppliers) that are labelling it wrong. Aug 17, 2011 at 17:40
  • With memory, the only thing you need to worry about is matching up the DDR version (DDR, DDR2, DDR3), the pin count (laptop, desktop), and the speed of the memory (1333mhz).
    – whardy
    Aug 17, 2011 at 17:51
  • I've never seen ram labeled that way before. It is just PC-speed. You tell whether it is DDR2 or DDR3 by the speed, not a number before the dash.
    – psusi
    Aug 17, 2011 at 17:54
  • got it. Thank you all for the quick replies! really appreciated
    – silverCORE
    Aug 17, 2011 at 17:55

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