Become a MacRumors Supporter for $50/year with no ads, ability to filter front page stories, and private forums.

keithtm

macrumors newbie
Original poster
Apr 3, 2008
3
0
had a search through the forum to no avail.

i have 2 new 2GB sticks (rated at 800Mhz). when i put them both in the machine, it won't boot past the black screen.

when i use either of them with either of the old 1GB sticks in either slot, system boots to 3GB no problem.

tried resetting PRAM, NVRAM and SMC but all to no avail.

difficult to understand whether the problem is with the machine or the ram - any suggestions?

thanks
 

Jiddick ExRex

macrumors 65816
May 14, 2006
1,469
0
Roskilde, DK

They should in theory take 800 mhz and downclock it to 667mhz but the new SR platform with a Penryn CPU has some problems using these (which CanadaRAM can explain much better than I can).

It might very well be because of the 800mhz that the OP is experiencing problems.

Why did you even buy 800mhz RAM in the first place? Wanted to use more money? :)
 

MacHappytjg

macrumors 65816
Mar 24, 2008
1,498
1
Winnipeg
They should in theory take 800 mhz and downclock it to 667mhz but the new SR platform with a Penryn CPU has some problems using these (which CanadaRAM can explain much better than I can).

It might very well be because of the 800mhz that the OP is experiencing problems.

Why did you even buy 800mhz RAM in the first place? Wanted to use more money? :)

yea its sopposed to be 667mhz ddr2 sdram well at least in my computer
 

riscy

macrumors 6502a
Jan 4, 2008
737
3
China
If as some people say, that speed will run on your MB (I dunno), check that you have pushed it in far enough - I just upgraded my RAM last weekend and really had to push it in to get it to house properly in the settings.

It took more oomph than I expected, it does not just glide in.
 

keithtm

macrumors newbie
Original poster
Apr 3, 2008
3
0
the memory was the same price as 667 ram. since it appeared too-fast-ram wasn't a problem, that it would just run it at 667, i thought there should be no problem.

i didn't think of trying just a single stick. i'll let you know how i get on.
 

CanadaRAM

macrumors G5
There is a well-known problem with 800 MHz memory not having properly written SPD values and being incompatible with Penryn Macs. So although theoretically they should clock down to 667, if they are not programmed properly, they won't work. One report is that they do work when installed one at a time with an Apple RAM in the other socket -- because the Apple RAM forces the machine to 667 CL5 timings with its correctly written SPD values. But with only 1 or 2 of the 800s it fails.

A case of false economy -- the 'faster' RAM gives you no speed benefit plus added grief.

MR Guide to Buying RAM

The other issue with MacBooks that is very common: not installing the RAM completely. When you push the RAM into the slot, it goes in about 1 inch and stops. It is not installed yet. You need to get both thumbs on the RAM and push hard, and it goes in another 1/8" or so (2mm for the eurocentric SI crowd. Here in Canada we're informally bimetric as well as legally bilingual. Or maybe that's polymetric. Can't remember)

Anyway, if you don't have dents in your thumbs, you haven't pressed hard enough.

The classic non-inserted RAM symptom is a pulsing white power light and a black LCD screen.
 

RedTomato

macrumors 601
Mar 4, 2005
4,155
442
.. London ..
where did you get your ram from, and which brand is it?

Like the other posters, aye, its 99% sure to be an issue with your new ram.
 

mlemonds

macrumors 65816
Apr 9, 2008
1,055
198
Lexington, KY
Did you try the ram in another computer?

could be some DOA ram. (something that only pops up when running dual channel)

just a stab in the dark

no brand is perfect.
 

mreg376

macrumors 65816
Mar 23, 2008
1,209
392
Brooklyn, NY
had a search through the forum to no avail.

i have 2 new 2GB sticks (rated at 800Mhz). when i put them both in the machine, it won't boot past the black screen.
Umm, it's always a good idea to install RAM that adheres to the specs established by the manufacturer, which in this case is NOT 800Mhz. So, if you ignore the specs and then have a problem, most people would suggest that as Troubleshooting Move Number 1 you use components that comply with the specs.
 

xraydoc

Contributor
Oct 9, 2005
10,741
5,171
192.168.1.1
Its not only Penryn Macs that have this issue - virtually any Mac on which you try RAM modules with incorrectly programmed SPD codes will fail. There's no BIOS to override the SPD code, so if the boot firmware can't read the SPD timing, it won't boot. This is why it'll work with one proper and one improper module - at least one module has proper timing codes.

Return the chips, buy Mac-tested RAM.
 

TrickyPhillips

macrumors newbie
Apr 8, 2008
1
0
There is a well-known problem with 800 MHz memory not having properly written SPD values and being incompatible with Penryn Macs. So although theoretically they should clock down to 667, if they are not programmed properly, they won't work. One report is that they do work when installed one at a time with an Apple RAM in the other socket -- because the Apple RAM forces the machine to 667 CL5 timings with its correctly written SPD values. But with only 1 or 2 of the 800s it fails.

A case of false economy -- the 'faster' RAM gives you no speed benefit plus added grief.

MR Guide to Buying RAM

The other issue with MacBooks that is very common: not installing the RAM completely. When you push the RAM into the slot, it goes in about 1 inch and stops. It is not installed yet. You need to get both thumbs on the RAM and push hard, and it goes in another 1/8" or so (2mm for the eurocentric SI crowd. Here in Canada we're informally bimetric as well as legally bilingual. Or maybe that's polymetric. Can't remember)

Anyway, if you don't have dents in your thumbs, you haven't pressed hard enough.

The classic non-inserted RAM symptom is a pulsing white power light and a black LCD screen.

Very informative, CanadaRAM. :)
 

photodude77

macrumors newbie
Apr 12, 2008
3
0
Memory Issue

I purchased Corsair Gaming Memory with the 800mhz. The reason I did was because I have always been under the impression that matching the bus speed on the computer will get the best performance. and since the macbook pro has a bus speed of 800mhz. enough said. I am able to use one 2gb stick of corsair gaming memory, and one of the 1gb sticks that came with the laptop making it 3gb of memory. if I put both 2gb sticks I just get the black screen. and it won't go on from there. I know its been mentioned before about the memory being an issue, but if it works with one stick, why not both? thanks for the help.
 

mreg376

macrumors 65816
Mar 23, 2008
1,209
392
Brooklyn, NY
I purchased Corsair Gaming Memory with the 800mhz. The reason I did was because I have always been under the impression that matching the bus speed on the computer will get the best performance. and since the macbook pro has a bus speed of 800mhz. enough said. I am able to use one 2gb stick of corsair gaming memory, and one of the 1gb sticks that came with the laptop making it 3gb of memory. if I put both 2gb sticks I just get the black screen. and it won't go on from there. I know its been mentioned before about the memory being an issue, but if it works with one stick, why not both? thanks for the help.

So you thought that 800Mhz memory gave better performance in the Mac than the RAM that Apple recommended but that Apple decided to hide that fact?
 

photodude77

macrumors newbie
Apr 12, 2008
3
0
Memory Issue

It is all hardware, it is just mac operating system, and windows operating system, its still hardware for memory. when building computers, matching the memory and the front bus is the best way to get the best performance. And of course Mac wants you to use Mac approved memory, its made from samsung, and Mac makes so much money off of it. but it doesn't matter what memory, its about the hardware, cause what makes Macs a Mac is the operating system. I think I mentioned Hardware a lot here.
 

xraydoc

Contributor
Oct 9, 2005
10,741
5,171
192.168.1.1
It is all hardware, it is just mac operating system, and windows operating system, its still hardware for memory. when building computers, matching the memory and the front bus is the best way to get the best performance. And of course Mac wants you to use Mac approved memory, its made from samsung, and Mac makes so much money off of it. but it doesn't matter what memory, its about the hardware, cause what makes Macs a Mac is the operating system. I think I mentioned Hardware a lot here.

But you forget that the "hardware" in the MacBook, despite using an 800MHz FSB in the Santa Rosa revisions, use only a 667MHz memory bus. Period. There is no 800MHz support. And there's no BIOS in which to attempt to overclock it to 800MHz.

You can (try) to put 500THz RAM in to the machine, but it'll still only run at 667MHz in the MacBook (and MBP, iMac and Mac mini).

In your post a few lines up, you speak about one 800MHz stick and one Apple stock stick working, but not both 800MHz sticks. The reason, as we've said, is because its only running at 667MHz - set by the stock Apple DIMM. The faster RAM isn't supply proper 667MHz-mode SPD codes to the Mac's firmware, so it fails to boot.
 

keithtm

macrumors newbie
Original poster
Apr 3, 2008
3
0
wow you guys are very passionate, but not so good at reading usernames.

wish i'd seen the thing about the apple not liking faster ram. i'd only read about the fact that faster memory should be capable of running slower.

i'll live with 3GB for the price i paid, and share a little memory love with my gf's macbook.

thanks for all the advice!
 

CWallace

macrumors G4
Aug 17, 2007
11,961
10,617
Seattle, WA
wish i'd seen the thing about the apple not liking faster ram. i'd only read about the fact that faster memory should be capable of running slower.

Your problem is not so much using "faster RAM" (I use 800MHz RAM in my iMac and MacBook that runs at 667MHz in both units), but that the RAM you purchased is not able to be properly configured for running at the 667MHz speed your MacBook runs it at.

I would recommend, if possible, returning both sticks and choosing another supplier. I use Crucial, for example.
 

photodude77

macrumors newbie
Apr 12, 2008
3
0
Memory

Red Tomato, wow, very funny. no I don't mean to sound defensive. at all. for the record, the sticks were just bad, and when I replaced them they work fine.
 

CanadaRAM

macrumors G5
It is all hardware, it is just mac operating system, and windows operating system, its still hardware for memory. when building computers, matching the memory and the front bus is the best way to get the best performance. And of course Mac wants you to use Mac approved memory, its made from samsung, and Mac makes so much money off of it. but it doesn't matter what memory, its about the hardware, cause what makes Macs a Mac is the operating system. I think I mentioned Hardware a lot here.
Umm.. right. And the Hardware has a 667 MHz memory bus.


wish i'd seen the thing about the apple not liking faster ram

For next time, have a look in the MacRumors Guides, under the Guides tab at the top of the window

Guides: Hardware: Understanding Intel Mac RAM
 
Register on MacRumors! This sidebar will go away, and you'll see fewer ads.