I have an HP-Pavilion dm4-1150ca. The CPU is a first gen. Intel Core i5 450m.

When I looked at the specifications page of this processor, I saw that it said only DDR3 800/1066 are compatible. However, the RAM that came physically installed with the laptop are (Micron) DDR3 1333MHz.

I used Crucial's advisor tool and it said PCL-12800/DDR3-1600 are compatible. Corsair's SODIMM Vengeance DDR3 claims to be backwards compatible with First gen Intel Core i5 processors. I just bought 2x4GB Corsair Vengeance RAM (which are DDR3L-1600). I am waiting on the arrival of the product for testing. I've read that generally RAM is more or less "plug-n-play". However, how come these manufacturers list contradictory compatibilities?

Is it because, implicitly RAM is compatible with most computers provided the DDR version is correct?

UPDATE: 2x4GB DDR3L 1600MHz SODIMM Corsair Vengeance installed, fully working. However, memory is being clocked-down to 1067MHz. Memory voltage is 1.35V

  • I would double check the Vengeance RAM to make sure it's rated for 1.35v / 1.5v. I've always heard mixed results about running low voltage RAM in a regular voltage RAM slot. Second, your sticks are probably not running at 1600 MHz. They are more than likely automatically being down-clocked by your memory controller.
    – DrZoo
    Nov 21, 2016 at 22:29
  • Sorry about the late pointless comment. This was in a review queue for a users first question. Glad you got your answer!
    – DrZoo
    Nov 21, 2016 at 22:30
  • @DrZoo Yes, thank you. I have updated my question accordingly.
    – Joe DF
    Nov 23, 2016 at 0:21

1 Answer 1


only DDR3 800/1066 are compatible

This is incorrect, it should read "memory supporting at least 400MHz or 533MHz".

(DDR3-800 runs at 400MHz with two actions per cycle. Marketing loves to present that as 800MHz. Which is about the same as saying "I have a car which drives 50kmph with two people in it, so it is a 100kmph car"...)

Staying with the car analogies, you are perfectly fine running a car capable to 160kmph on a highway at 120kmph speeds. It does not matter that it can go faster, but it must at least be able to drive 120kmph. Same with your memory. Yours DDR3-1600 can do 800MHz (DDR-1600), 533MHz (DDR-1333) or 400MHz (DDR3-800).

The only thing which you really want o pay attention to is the difference between DDR3 and DDR3L. Normal DDR3 operates at 1.5volt. It may or may nor work at other voltages. DDR3-L operates at 1.35v (and likely also works at 1.5v or 1.65v). You do not want to do this the wrong way around (e.g. a DDR3L only system with regular DDR3).

The last should not bother you today, but it is something to keep in your mind when you upgrade. Modern systems (and thus upgrades) usually use DDR4 or DDR3-L.

  • Concise answer, I truly appreciate it :)
    – Joe DF
    Nov 18, 2016 at 14:42
  • Another thing to watch for when maxing out an older system is "rank". I put a 4GB single rank module in a first-gen i5 laptop and it didn't work, but a dual rank 4GB module (which is what would have existed at the time the laptop was designed) worked fine.
    – plugwash
    Aug 9, 2018 at 20:34
  • Rank is worth watching, but most home user DIMMs are rank-2. You really have to spent some effort to get rank 1 or rank 4. For server memory it is different. And I guess for really old systems with modern memory with higher capacity memory chips. Which is probably where you ran into problems with.
    – Hennes
    Aug 9, 2018 at 21:11

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