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tungtied07 Apr 7, 2007 05:14 PM
533Mhz DDR2 SODIMM in MacBook
I have a 2.0Ghz MacBook Core 2 Duo Notebook. It originally came with 1GB (2x512) DDR2 667Mhz Memory. However, I had some old memory from my old notebook that used DDR2 533Mhz SODIMM Memory. I used those 2 1GB SODIMMS to upgrade to 2GB of memory. However, after 5 Months, I did not realize until now that the memory is 533Mhz, not 667Mhz. Does it make that much of a difference I am using 533Mhz memory? Will I notice a difference if I were to get 667Mhz memory instead? It is working perfectly with 2GB of DDR2 533Mhz SODIMM memory, but am I holding my system back alot?
Thanks, Paul
C.A.T.S. CEO Apr 7, 2007 06:19 PM
I'm pretty sure you won't have a problem with it, I heard of somebody doing the same and he didn't notice much lag
imitchellg5 Apr 7, 2007 06:25 PM
Yes it makes a difference, and you should go back to 667 MHz. I've mixed 533 MHz with 667 MHz too and that wasn't so good.
mfbernstein Apr 7, 2007 07:24 PM
Could you elaborate on the drawbacks? I've been running with 3GB (2GB 533MHZ that was mislabeled as 667, 1GB 667MHZ) for almost a month now on my MBP C2D, and I haven't noticed anything in particular amiss.
chipchen Apr 8, 2007 07:07 AM
draw back is speed. The bus is rated for 667 and the CPU uses that to calculate a certain multuplier for clock speed. Slower RAM, means everything else has to clock down to match it. Basically, you could be running at only 80% CPU speed.
mfbernstein Apr 8, 2007 07:54 AM
That's not really true though. Unless all your application is doing is reading and writing to memory, the handicap will be far less than 20%. Moreover, I'm running Core2DuoTemp, and my CPU clock is still reported at 2.16GHZ. As for the whacked CPU/Bus ratio, once again, if the original machine is running with a 3.25:1 multiplier, how is running at 4.05:1 such a tragedy?
chipchen Apr 8, 2007 08:24 AM
Then keep your configuration. Don't change it. No one told you to. You asked what the drawbacks are.

The truth is... speed. Will you notice this in the real world? Probably not. As you haven 't. But that doesn't mean it isn't happening. Bottom line... you're the only one it affects. And if you don't care, leave it.
mfbernstein Apr 8, 2007 08:28 AM
I was curious as to the specific drawbacks. A 20% across-the-board drop in speed would be quite noticeable, IMO. My guess is that for non-synthetic tests, you'd be hard-pressed to see more than a 5% difference, but if you've got examples, I'd be interested in hearing them.
Alnitak Apr 8, 2007 03:25 PM
Contrary to what chipchen posted, it DOES NOT slow down your CPU. The CPU frequecy remains the same; it's just memory access that is degraded. On the other hand, I tried this just for fun, and what I found was that mixing 533 and 667 RAM resulted in a noticeable increase in the fequency of kernel panics (what I like to call "Black Multi-lingual Screens of Death, BMSD). Increase, as in, before the RAM I might get one every few months if I installed a bad happening once every day or to with mixed RAM. This was with Crucial RAM, both from the same chip quality RAM. The MacBook Pro I tried it in sure didn't like the mix..
OtisWild Apr 9, 2007 10:51 AM
Keep in mind also that on the Macbook, video speed is dependent on RAM speed. So, if you do even mild gaming on the Macbook, you'll be better off with 667.
frdmfghtr Apr 10, 2007 10:54 PM
OT: Got a link to Core2DuoTemp? I tried Google but found references to it in forum posts but no software.
tungtied07 Apr 10, 2007 11:20 PM
Wow, thanks for the replies everyone! I ended up selling the memory chips and going to get the correct memory. Do you all recommend Crucial memory or will brands like these work well too? - mushkin 2GB (2 x 1GB) 200-Pin DDR2 SO-DIMM DDR2 667 (PC2 5300) Dual Channel Kit Notebook Memory - Retail - G.SKILL 2GB (2 x 1GB) 200-Pin DDR2 SO-DIMM DDR2 667 (PC2 5300) Dual Channel Kit Notebook Memory - Retail

2GB kit (1GBx2), 200-pin SODIMM, DDR2 PC2-5300 upgrades for Apple MacBook 2.0GHz Intel Core 2 Duo (13-inch White) Laptop/Notebook, CT613250 from

Of these 3, which one will you all recommend?
Thanks for the help everyone!!
mfbernstein Apr 11, 2007 07:47 AM
Get the Mushkin or the Crucial. Crucial has the better reputation, but they're both good vendors. I'd stay away from G.Skill: as mentioned above, the mislabeled their DDR2 533 2GB sticks as DDR2 667. Not cool, and they're not even that much cheaper.
mduell Apr 11, 2007 01:36 PM

I'd take Crucial even if it was a bit more expensive than mushkin.
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