Upgrade from 2x1gb to 2x2gb RAM not working

I have a brand new 15" macbook pro which I've purchased new RAM for and today tried to install. Very weird results. Either 2gb module will work in concert with a factory 1gb module, yielding 3gb. But, neither of the 2gb modules will work by themselves or together as a 4gb set. In both of the later situations I push the power button and the cd drive makes a sound but then nothing happens, screen doesn't kick on and OS doesn't start.

Like I said, both 2gb sticks work with a 1gb stick, but no other way.

Anyone familiar with this problem?

Thanks

The thread you linked to only addressed models from 2007. Mine is the new 2008 line.

(also, what does it mean to take 4gb but only address 3gb)

means it might able to only recognize the 3gb despite the 4gb you have

that doesn't make sense in the context of it being a new mac 4gb capable, and weird that the 2gb modules don't work by themselves either... any other ideas out there?

kylelamb75 said:

I have a brand new 15" macbook pro which I've purchased new RAM for and today tried to install. Very weird results. Either 2gb module will work in concert with a factory 1gb module, yielding 3gb. But, neither of the 2gb modules will work by themselves or together as a 4gb set. In both of the later situations I push the power button and the cd drive makes a sound but then nothing happens, screen doesn't kick on and OS doesn't start.

Like I said, both 2gb sticks work with a 1gb stick, but no other way.

Anyone familiar with this problem?

Thanks

Click to expand...

im gonna go ahead and guess it is the ram itself, i would purchase another 2x2gb stick from elsewhere and see if they work, the worst that can happen is you will have to return them

So you've tried both 2GB sticks in conjunction with a single 1GB stick and it boots up just fine, but when you throw in a single 2GB stick or both 2GB sticks, it doesn't boot up?

Kash said:

So you've tried both 2GB sticks in conjunction with a single 1GB stick and it boots up just fine, but when you throw in a single 2GB stick or both 2GB sticks, it doesn't boot up?

Click to expand...

yep. exactly. so they appear to work, but only in combination with a 1gb stick...

I purchased a Macbook Pro. 15" 2.5ghz. with 512mb Video ram. It came with 2x1GB ram sticks, and I was able to use 2x2GB ram sticks by Kingston. It recognizes 4gb as well as Vista 64-bit/Bootcamp recognizes it as well.

Ram I Bought

kylelamb75 said:

yep. exactly. so they appear to work, but only in combination with a 1gb stick...

Click to expand...

Return the ram.

Go to Crucial.com and if you're not sure which RAM to purchase after following the menus they will scan your computer to tell you what you need.

Great RAM quality, service and support.

Any luck?

Ok, I have the same problem. Here's the details that are germane.

I run engineering at a small shop that runs all MBP machines. I bought RAM (2x2GB from Edge) for 3 machines. The one we tried to install is the newest machine, bought a month ago or so (2.6 GHz MBP 15").

At first it failed to boot like the original poster. We took it out, tried a second batch, same fail. Put the original back in, booted fine. Took the two open packages, put them in the other two MBPs (2.16 GHz) and they both booted great.

Opened the third package of RAM, dropped it into the 2.6GHZ and it didn't boot with the 4 Gig of memory. Dropped one of the original 1G into the machine and booted fine with 3 G total. Switched out the sticks, booted great.

So I left the new machine stuck with 3G while I sorted this out.

Any ideas other than a) seating memory and b) where I got the memory? I know the memory is seated right (I've personally done 6 upgrades in the last 2 days so....) and the memory from Edge has been flawless in the other machines we've used it in.

This has to be a machine thing, especially with the newest of macs.

Any additional help would be great.

Cory

Is the memory by any chance 800mhz?? I've just bought 2x2GB 800MHZ DDR2 memory and ran into the same problem, it would not boot up, even with just one of them in, until I added a smaller memory (which was 667MHZ) I went into the About This Mac menu, and sure enough, it said it was running at 667MHz. I think the mac is limited to 667MHz and it won't boot with a faster stick.