MBP not recognizing 800 MHz DDR2

[rmortensen]

Just purchased 2 Corsair 2GB DDR2 800MHz sticks to upgrade MBP. Installing both sticks doesn't work but using one of the original 1GB and one of the new 2GB sticks allows machine to start and show 3GB active at 667MHz. Is there a work-around to make the MBP recognize the two 800MGz sticks or should I simply return the two new sticks to BBY? I've searched prior threads but not finding this specific question.

 

[electroshock]

First of all, welcome to MacRumors!

Second, what is the exact MBP model that you have? Which year (and time of year -- i.e. early, mid, late) and if it's an unibody or not, speed of the processor (2.4 GHz, 2.8, whatever).

Third, do you have a link to the exact product you bought?

Knowing the answers to both questions may help narrow down the exact culprit.

 

[rmortensen]

MBP4.1 15.4" purchased March 2008, 2.4 GHz Intel Core 2 Duo

unibody/grey keys

Link to Corsair product is http://www.bestbuy.com/site/olspage.jsp?skuId=8724767&type=product&id=1200703058546

 

[ayeying]

use 667MHz. 800MHz won't be as compatable as 667MHz on this model and you might run into problems

 

[rmortensen]

so, using the 1GB original stick adjusts the new 2GB stick to the 667MHz but the two 2GB sticks together will not tool down to the 667MHz thus the machine won't even start with the total of 4GB - right?

In other words, using the 1GB and 2GB works fine with the ratchet down to the 667MHz and runs at 3GB just fine

 

[electroshock]

so, using the 1GB original stick adjusts the new 2GB stick to the 667MHz but the two 2GB sticks together will not tool down to the 667MHz thus the machine won't even start with the total of 4GB - right?

In other words, using the 1GB and 2GB works fine with the ratchet down to the 667MHz and runs at 3GB just fine

Yeah, I'd agree that's likely what's indeed happening.

 

[rmortensen]

Ok - thanks. It appears the best solution is to simply return both 2GB sticks tomorrow and get the 667 MHz.