RAM issue with White Macbook

Drunken_King

[H]Lite
Joined
Jan 12, 2007
Messages
111
Hello Everyone. I have a White Macbook Early 2008 which originally came with 2 GB of memory. Since I use VMWare a lot i decided to get a pair of 2GB sticks to double my RAM. So I removed original RAM and installed the new RAM but when I turned it on nothing happens. So I thought maybe it's a stick of RAM. So I tested one stick with one of my original 1GB Sticks. The computer booted perfectly. Tried it again with the other 2GB Stick and it worked. But when I put in both 2GB sticks in the slots the computer won't boot. What could the problem be?
 

disuse_nc

Limp Gawd
Joined
Apr 17, 2007
Messages
208
What are your new sticks of ram? (Manufacturer/Model/Part Number)

I assume that the manufacturer supports the Apple Macbook w/ the ram?
 

sed8em

2[H]4U
Joined
Apr 2, 2007
Messages
2,346
I had the exact same problem with my 2008 2.4ghz Macbook Pro. I'm running at 3gb now, 1gb original RAM and 2gb stick of the upgrade RAM.
 

cbags101

Gawd
Joined
Nov 26, 2006
Messages
751
make sure its not pc2-6400 (800mhz) ram. In my experience, the white macbooks wont underclock to the 667mhz. It has to be pc2-5300.
 

sed8em

2[H]4U
Joined
Apr 2, 2007
Messages
2,346
make sure its not pc2-6400 (800mhz) ram. In my experience, the white macbooks wont underclock to the 667mhz. It has to be pc2-5300.
You may have hit the nail on the head my friend.
I purchased Kingston 2gb sticks of PC2-6400, and my Macbook Pro came with Samsung PC2-5300 speed RAM.
So currently I'm running a stock Samsung 1gb 667 stick and a Kingston 2gb 800 stick together for a total of 3gb, no problems there. Can't do 2 sticks of Kingston 2gb 800 though, no boot, just like the OP is claiming.

Did the 2008 white Macbook and the 2008 (pre-unibody) Macbook Pro's come with the same chipset, which could cause them to both have the need to use PC2-5300 RAM?

If so I should be able to just to go Newegg and get some 2gb PC2-5300 RAM from any reputable RAM manufacturer and stick it in? I've noticed the Apple specific RAM from the electronics retailers seems to be higher priced than the stuff they sell for any notebook.
 

cbags101

Gawd
Joined
Nov 26, 2006
Messages
751
You may have hit the nail on the head my friend.
I purchased Kingston 2gb sticks of PC2-6400, and my Macbook Pro came with Samsung PC2-5300 speed RAM.
So currently I'm running a stock Samsung 1gb 667 stick and a Kingston 2gb 800 stick together for a total of 3gb, no problems there. Can't do 2 sticks of Kingston 2gb 800 though, no boot, just like the OP is claiming.

Did the 2008 white Macbook and the 2008 (pre-unibody) Macbook Pro's come with the same chipset, which could cause them to both have the need to use PC2-5300 RAM?

If so I should be able to just to go Newegg and get some 2gb PC2-5300 RAM from any reputable RAM manufacturer and stick it in? I've noticed the Apple specific RAM from the electronics retailers seems to be higher priced than the stuff they sell for any notebook.
I had no idea you could run 1 stick of 667 and one stick of 800 and it would boot and recognize all 3gb that way. interesting. you can pretty much order any SODIMM 200-pin DDR2-667mhz ram, it doesn't have to be "mac specific" and save yourself $10 or so on retail prices.

as for the 2008 mbp, i believe its the same they updated the fsb to 800mhz, but kept the ram clocked at 667mhz...
 

delvryboy

2[H]4U
Joined
Feb 21, 2008
Messages
2,486
Any pc2-5300. I picked up 4gb of OCZ for $25 ar back when "Mac " ram was $200 for 4gb. It's been running great for almost 2 years.
Posted via [H] Mobile Device
 

Drunken_King

[H]Lite
Joined
Jan 12, 2007
Messages
111
Theres a flaw with either the Intel chipset or the apple EFI or both. Im guessing the EFI as the Intel chipset exists in other laptops and we have not heard anything on other laptops having this issue.

Anyway, my solution was this:

*****DISCLAIMER: I take no responsibility for voiding RAM warranty or harming the computer by using this program********

Boot into bootcamp (one 800mhz ram stick one 667mhz ram stick) and use this:
http://forums.techpowerup.com/showthread.php?t=20349

Change the CAS to 3ns from 2.5ns to make the RAM 333Mhz (with dual data rate thats 666, oh but thats evil, better round up the .1 to 667)

Make sure to use the "edit change checksum" or something of the like. Just DO NOT WRITE THE DATA WITH INVALID CHECKSUM!!! You only really need to do this with 1 RAM stick as the other one will be throttled down to match the lower speed by the chipset (oh right, it works, go figure its an EFI problem).

Anyway, enjoy this hotfix until Apple fixes their proprietary hardware interface software. If you break your RAM, tough luck, complain at Apple or accept the responsibility that you didn't know what you were doing and broke it.
Sorry everyone I took so long to respond but I completely forgot to post after I got it working. Thank God I found this fix. Saved me from exchanging the memory. Just downloaded SPDTool and used it in Windows via Boot Camp. Changed the CAS of one 2gb stick to 3ns (333mhz) from the original 2.5ns (400mhz) and voila the other stick throttled down. Hope this helps anyone with this problem. Any questions feel free to ask. Link to SPDTool http://www.techpowerup.com/spdtool/SPDTool_063.zip
 
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