[Pao|o]

After I installed 16GB DDR3-1600, the MBPro now much faster but i've been testing it using CAD, 3D renderers and games - and it reboots when doing higher level computations.

I pulled out the new RAM and plugged in my original RAM for testing, and works fine.

I am using a MacBookPro8,2 Early 2011 15" Core i7 (I7-2635QM) with a pair of F3-1600C10D-16GSQ.

Did I get bad RAM?

[steve626]

Originally Posted by Pao|o 

After I installed 16GB DDR3-1600, the MBPro now much faster but i've been testing it using CAD, 3D renderers and games - and it reboots when doing higher level computations.

I pulled out the new RAM and plugged in my original RAM for testing, and works fine.

I am using a MacBookPro8,2 Early 2011 15" Core i7 (I7-2635QM) with a pair of F3-1600C10D-16GSQ.

Did I get bad RAM?

The Mac you are using supports
1333 MHz PC3-10600 DDR3 SDRAM. You are using a different type of RAM,
DDR3-1600 PC3-12800. I suspect this is incompatible with your Mac. G.Skill shows the RAM you are using as for PC's, not for Macs, and specifically lists other compatible RAM chips for your Mac.

G.SKILL- World leading DDR3 computer memory and SSD manufacturer -Products

I think your experience proves empirically as well that the RAM chips you installed are incompatible. You should follow Apple's and G.Skills recommendations carefully when installing RAM.

In the end, you can't beat physics, and incompatible RAM just won't work right. I suspect your RAM is fine, but it is incompatible with your model of computer.

This is the second post where you've indicated that you have put incompatible RAM in your Macs and are wondering why it doesn't work. This is like putting the wrong spark plugs in an automobile -- I wouldn't do it.

[Pao|o]

The F3-1600C10D-16GSQ kit works on a MacBookPro8,1 Early 2011 13" Core i7 (I7-2620M)


I ran memtest but 12 gigs was only detected.

Mac OS X 10.8.2 (12C60) running in multiuser mode
Memory Page Size: 4096
System has 8 Intel core(s) with SSE
Requested memory: 12198MB (12790575104 bytes)
Available memory: 12198MB (12790575104 bytes)
Allocated memory: 12198MB (12790575104 bytes) at local address 0x0000000101000000
Attempting memory lock... locked successfully
Partitioning memory into 2 comparison buffers...
Buffer A: 6099MB (6395287552 bytes) starts at local address 0x0000000101000000
Buffer B: 6099MB (6395287552 bytes) starts at local address 0x000000027e305800

Running 2 test sequences... (CTRL-C to quit)

Test sequence 1 of 2:

Running tests on full 12198MB region...
Stuck Address : testing 7 of 16

FAILURE! Data mismatch at local address 0x000000035be63818
Actual Data: 0xbffffffca419c7e7

Linear PRN : ok
Running comparison tests using 6099MB buffers...
Random Value : ok
Compare XOR : ok
Compare SUB : ok
Compare MUL : ok
Compare DIV : ok
Compare OR : ok
Compare AND : ok
Sequential Increment: ok
Solid Bits : testing 16 of 64

FAILURE! Data mismatch at local BUFA address 0x000000017f551618, BUFB address 0x00000002fc856e18
BUFA Data: 0xbfffffffffffffff, BUFB Data: 0xffffffffffffffff

Block Sequential : ok
Checkerboard : ok
Bit Spread : ok
Bit Flip : setting 187 of 512

Then it failed. Could it be a mis-seat? From what I understand if one of the modules is unseated - it should read 8 gigs only. Since 12 was read - one side of the RAM chips on one board could be defective?

FAILURE! Data mismatch at local BUFA address 0x000000017f551618, BUFB address 0x00000002fc856e18
BUFA Data: 0xbfffffffffffffff, BUFB Data: 0xffffffffffffffff

Block Sequential : ok
Checkerboard : ok
Bit Spread : ok
Bit Flip : testing 408 of 512

FAILURE! Data mismatch at local BUFA address 0x00000001342eb8a8, BUFB address 0x00000002b15f10a8
BUFA Data: 0xfffffffffffbffff, BUFB Data: 0xbffffffffffbffff

[steve626]

It's hard to say exactly what your problem is because the manufacturer lists your memory pack as "Notebook Memory FOR PC" here: G.SKILL- World leading DDR3 computer memory and SSD manufacturer -Products

It lists other, different memory chips separately under "Notebook Memory FOR MAC"

For instance

G.SKILL- World leading DDR3 computer memory and SSD manufacturer -Products

It looks from your memory test that your Mac isn't properly recognizing all the memory that the manufacturer says is for "PC Notebooks." The manufacturer might argue that this is because you are using memory that they have not specc-ed for your Mac, not because there is anything wrong with the memory.

Do you have any memory sticks you can try that the manufacturer recommends be used with your model of Macbook Pro?

The Apple Discussion boards are full of posts from people who have tried memory in their Macs that various manufacturers have specc-ed for use in other types of computers or did not spec for use with their Macs; and many complain of booting or other problems.

[P]

I think you have a bad stick of RAM. All DDR3 memory must be backwards compatible with lower frequencies according to JEDEC specification, so it's not that. There is no "Mac memory" and "PC memory" - that's a historical artifact.

[Pao|o]

Originally Posted by P 

I think you have a bad stick of RAM. All DDR3 memory must be backwards compatible with lower frequencies according to JEDEC specification, so it's not that. There is no "Mac memory" and "PC memory" - that's a historical artifact.

I agree but why do some memory modules work on a PC laptop while they fail on Mac notebooks?

F3-1600C10D-16GSQ kit also works on a MacBookPro8,1 Late 2011 13" Core i7 (I7-2640M)

[shifuimam]

Hold up.

RAM does not need to be listed as "Mac compatible" in order for it to work. As long as it meets the specifications for type (DDR2, DDR3, etc), size (SO-DIMM versus DIMM), and ECC or buffering (Mac Pros require buffered ECC RAM whereas other Macs do not), it should be compatible.

RAM is RAM. The little silicone chips soldered to a circuit board are all the same - there are a handful of RAM manufacturers out there, and one brand is not inherently better than another. I've used random third-party brands I've never heard of, like Avant, along with brand-names like Crucial and Hynix, and they're all the same. It sounds like you simply got a defective stick of RAM. One or more of the bits on at least one of the chips is defective, and as soon as the computer tries to access that defective bit, it shits itself and reboots.

Macs have a history of being a little picky with certain specific sticks (I used two different brands in a PowerMac G3 and it KPed a lot), but it's not likely to show itself as errors when doing memory-heavy stuff. It's going to be more like total system freezes, kernel panics, or a complete inability to boot.

RMA the RAM. Just about any non-OEM RAM has a lifetime warranty on it. You should be able to get it replaced very easily. If you bought it at a retail store like Fry's or Micro Center, just exchange it (it'll be faster than an RMA).

To steve - please stop spreading misinformation. There are a variety of reasons why any RAM would have a problem in a computer, Mac or otherwise, and half the time it's because the RAM isn't properly installed or the person installing it didn't ground themselves and managed to blow a stick from ESD. It has nothing to do with a website specifying whether or not a stick is "Mac compatible" or not. That's just FUD.

[OreoCookie]

Just one more comment on RAM: one essential component on RAM stick is a chip that sets timings correctly. Manufacturers of cheap RAM (and curiously also manufacturers of high-end, overclockable RAM) have been notorious for just not doing their homework, especially when it comes to timings at lower clock rates.

But even if that were the case, you have no choice but to get the RAM module replaced.

[Pao|o]

I agree but as OreoCookie mentioned it appears corners are being cut so it can and cannot work. If this is the case why can't the spec be more economical then?

Originally Posted by shifuimam 

Hold up.

RAM does not need to be listed as "Mac compatible" in order for it to work. As long as it meets the specifications for type (DDR2, DDR3, etc), size (SO-DIMM versus DIMM), and ECC or buffering (Mac Pros require buffered ECC RAM whereas other Macs do not), it should be compatible.

RAM is RAM. The little silicone chips soldered to a circuit board are all the same - there are a handful of RAM manufacturers out there, and one brand is not inherently better than another. I've used random third-party brands I've never heard of, like Avant, along with brand-names like Crucial and Hynix, and they're all the same. It sounds like you simply got a defective stick of RAM. One or more of the bits on at least one of the chips is defective, and as soon as the computer tries to access that defective bit, it shits itself and reboots.

Macs have a history of being a little picky with certain specific sticks (I used two different brands in a PowerMac G3 and it KPed a lot), but it's not likely to show itself as errors when doing memory-heavy stuff. It's going to be more like total system freezes, kernel panics, or a complete inability to boot.

RMA the RAM. Just about any non-OEM RAM has a lifetime warranty on it. You should be able to get it replaced very easily. If you bought it at a retail store like Fry's or Micro Center, just exchange it (it'll be faster than an RMA).

To steve - please stop spreading misinformation. There are a variety of reasons why any RAM would have a problem in a computer, Mac or otherwise, and half the time it's because the RAM isn't properly installed or the person installing it didn't ground themselves and managed to blow a stick from ESD. It has nothing to do with a website specifying whether or not a stick is "Mac compatible" or not. That's just FUD.

[OreoCookie]

Originally Posted by Pao|o 

I agree but as OreoCookie mentioned it appears corners are being cut so it can and cannot work. If this is the case why can't the spec be more economical then?

What do you mean, more economical? Usually, the »fastest timings« tend to be implemented, it's the timings for when you drive the RAM at slower speeds where corners are cut. And it's not as complicated as it sounds (in theory). This can usually be avoided by spending a few € more (usually marginally more, often single-digit amounts). Often, the more conservative brand manufacturers tend to have better quality control, too.

But again, we don't know whether it's a problem of not properly implemented timings here, and shifuimam's post is also entirely correct.

[Pao|o]

Originally Posted by OreoCookie 

What do you mean, more economical? Usually, the »fastest timings« tend to be implemented, it's the timings for when you drive the RAM at slower speeds where corners are cut. And it's not as complicated as it sounds (in theory). This can usually be avoided by spending a few € more (usually marginally more, often single-digit amounts). Often, the more conservative brand manufacturers tend to have better quality control, too.

But again, we don't know whether it's a problem of not properly implemented timings here, and shifuimam's post is also entirely correct.

For all we know the SODIMM I got will work well with a PC laptop. I decided to have it RMAd. Just need to check make sure the rest of my kits are defective so I will send them all in one batch.

[P]

Originally Posted by Pao|o 

I agree but why do some memory modules work on a PC laptop while they fail on Mac notebooks?

Different RAM tests at boot, probably - or just that the PC laptop didn't use every last byte of RAM and didn't notice.

Originally Posted by Pao|o 

I agree but as OreoCookie mentioned it appears corners are being cut so it can and cannot work. If this is the case why can't the spec be more economical then?

Low-end RAM fails because it doesn't adhere to the spec. For high-end RAM, my guess is it is because they try to make their chips work as well as they can at clockspeeds that JEDEC hasn't approved yet.