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6GB in MacBook (Pro); Yes it works. - 8GB... well...

ayeying said:
If I add 1x4GB and 1x2GB, totaling 6GB; or just using 1x4GB; do I lose dual channel?
- Yes, you do lose dual channel.

Is losing Dual Channel a huge performance hit?
- Not really. It all depends on what you use it for. If you're doing a lot of modeling/rendering, dual channel might be a great help. For an average user or someone who runs memory hungry apps such as Virtual Machines, it is not much of an hit.
Click to expand...

I believe the computers support hybrid dual channel which means up to the amount of the smaller chip is dual channel and the rest is single channel, so for 2GB + 4GB, the 2GB in the first chip is paired with the first 2GB of the 4GB stick for dual channel performance.

Mastamarek said:
***** POS product, hope the whole apple team burns alive then!!! took my $2850 with tax for this POS laptop that I cant even upgrade. ***** worthless company!!! back to windows again. f*** that, f*** apple, f*** computers!!
Click to expand...

Actually I retracted my response, since I may be wrong. But when I had the computer it didn't support 8GB of RAM.
 
Mastamarek said:
***** POS product, hope the whole apple team burns alive then!!! took my $2850 with tax for this POS laptop that I cant even upgrade. ***** worthless company!!! back to windows again. f*** that, f*** apple, f*** computers!!
Click to expand...

i dont know what your complaining about. you knew the limit was 4GB when you purchased the computer.

the limit is actually 6GB, 8GB will run but very slowly (and might freeze).
 
DoFoT9 said:
i dont know what your complaining about. you knew the limit was 4GB when you purchased the computer.

the limit is actually 6GB, 8GB will run but very slowly (and might freeze).
Click to expand...

I really dont think that asking for 8Gb support in a 2009 product is too much to ask from a company as successful as Apple. If they want to break PC monopoly they have to get things straighten out and making more ram available is like the easiest thing a company can do on a hardware support side.

what do you mean 8gb will run slow?
 
Mastamarek said:
I really dont think that asking for 8Gb support in a 2009 product is too much to ask from a company as successful as Apple. If they want to break PC monopoly they have to get things straighten out and making more ram available is like the easiest thing a company can do on a hardware support side.

what do you mean 8gb will run slow?
Click to expand...

one thing to point out here is that apple does not want to break the PC monopoly. steve jobs has said this himself.

anyway, 8GB will be "recognised" by your computer, but it will not work properly/efficiently. it will freeze when more then 4GB has been addressed.

why do you need so much anyway? are you sure that you are using all 4GB atm? what are your page ins/outs/swap file?

can you not sell your current MBP and upgrade to a newer MBP that supports 8GB of RAM?

if you were going to put in the money (its about $700 to get 8GB), then you may as well upgrade computer too.
 
I do a lot of video and photoediting. Avid/Final Cur and CS4. Sometimes in activity monitor I only have 200Mb free of ram when doing heavy stuff. good thing about 6gb is that I only need to buy one stick of 4GB DRR3. I will loose dual channel though!! stupid !!! sooo mad right now!! how will 6gb non dual channel affect my everyday performance to the CS4 and Final Cut performance?
thx in advance
 
Mastamarek said:
I do a lot of video and photoediting. Avid/Final Cur and CS4. Sometimes in activity monitor I only have 200Mb free of ram when doing heavy stuff. good thing about 6gb is that I only need to buy one stick of 4GB DRR3. I will loose dual channel though!! stupid !!! sooo mad right now!! how will 6gb non dual channel affect my everyday performance to the CS4 and Final Cut performance?
thx in advance
Click to expand...

200mb free does not really tell me if you need new RAM. open up activity monitor, go to the "memory" tab down the bottom, and tell me your page ins/outs and swap file size. that will indicate whether you actually need new RAM.

as alphapod said earlier, if you have 6GB then you can still have dual channel. 2GB stick + 2GB from 4GB stick will be in "dual channel" mode. the other left over 2GB from the 4GB stick will not.

edit: be back later, laptop is going flat.
 
DoFoT9 said:
200mb free does not really tell me if you need new RAM. open up activity monitor, go to the "memory" tab down the bottom, and tell me your page ins/outs and swap file size. that will indicate whether you actually need new RAM.

as alphapod said earlier, if you have 6GB then you can still have dual channel. 2GB stick + 2GB from 4GB stick will be in "dual channel" mode. the other left over 2GB from the 4GB stick will not.
Click to expand...

I ll have to note those digits down when I edit. Right now my page in is only 160mb. lol. But I only have firefox running. CS4 though can bog down when I edit high pixel count files for print. Then I noticed I only have 200mb left as free. so the 2+2 will be dual channel and the other 2 will not. Will I notice any performance slow down when not editing my work? aka firefox open with lots of tabs?

vista.john said:
yes!
Click to expand...

what do you mean yes? I mean, like properly working, not the cripple version.
 
Mastamarek said:
I ll have to note those digits down when I edit. Right now my page in is only 160mb. lol. But I only have firefox running. CS4 though can bog down when I edit high pixel count files for print. Then I noticed I only have 200mb left as free. so the 2+2 will be dual channel and the other 2 will not. Will I notice any performance slow down when not editing my work? aka firefox open with lots of tabs?
Click to expand...

page ins are not really as important as the swap file and page outs. that is your real indicator. let us know the numbers when you see them :)

i dont think you will notice any slow downs at all. more RAM = faster computer. 2/3 of the RAM will be in dual channel, the other 1/3 is only twice as slow - still thousands of times faster then virtual memory!
 
DoFoT9 said:
page ins are not really as important as the swap file and page outs. that is your real indicator. let us know the numbers when you see them :)

i dont think you will notice any slow downs at all. more RAM = faster computer. 2/3 of the RAM will be in dual channel, the other 1/3 is only twice as slow - still thousands of times faster then virtual memory!
Click to expand...

The ram is either all dual channel all single channel. You will probably never notice a speed difference, and I don't think your RAM speed will be cut in half. For some reason I remember the difference being something like 1%, but that doesn't make sense or they wouldn't have dual channel in the first place. Maybe MBPs are all single channel?
 
m85476585 said:
The ram is either all dual channel all single channel. You will probably never notice a speed difference, and I don't think your RAM speed will be cut in half. For some reason I remember the difference being something like 1%, but that doesn't make sense or they wouldn't have dual channel in the first place. Maybe MBPs are all single channel?
Click to expand...

fair enough. so it will all be single channel. i was just going off what another person said.

macs all use double data rate memory, thus the DDR part stated on the apple webpage. wiki SD RAM, the first line here states that its double data rate. so that rules that out.

i would think that its a bit more then a 1% speed increase. it has twice the amount of cycles, so theoretically twice the amount of stuff it can handle. in practical exercises its probably maybe 1.5x as fast?
 
DDR is not the same as dual-channel. DDR just means the memory sends data twice per clock cycle, so DDR2-800 runs at 400MHz but acts like 800MHz RAM. The configuration of RAM modules doesn't affect DDR - it always operates as DDR.

2-channel means that there are 2 independent RAM channels that can send data to the CPU at the same time. Dual-channel requires matched modules.

I was reading this
http://developer.apple.com/legacy/m...l/HWTech_RAM/Articles/RAM_implementation.html
and it sounds like the MBPs are not dual channel, no matter what configuration of RAM modules you have. It isn't clear, but the article only mentions channels for the MP, Xserve, and some iMacs. It does say the MBP uses interleaving if the memory modules are matched. I can't find much on interleaved memory, but I suspect that is the only thing that affects performance when going from 2x2gb to 2+4gb.

http://en.wikipedia.org/wiki/Interleaved_memory
 
The intel 945G chipset (not used in MBPs, I don't think) supports "flex memory" or dual channel with unmatched memory modules. Does anyone know what chipset the non-Nvidia9400 MBPs use, and if it supports asymmetric dual channel?

http://www.intel.com/products/desktop/chipsets/945g/945g-overview.htm

Edit:
Santa Rosa MBPs use the Intel PM965, which does support asymmetric dual channel.
http://www.intel.com/Assets/PDF/datasheet/316273.pdf

That's why there is only a slight performance difference between matched and unmached modules. I'll try to figure out of the 9400-based MBPs support it, but I doubt their documentation will be as good as Intel's. I would guess they do support dual-channel.

Edit2:
Nvidia will apparently only give their datasheets to companies with NDAs. From the specs on the 9400M chipset, it looks like it has at least some kind of dual-channel, since it uses a 128 bit memory interface, or 64 bits per channel. Benchmarking should readily show if there is a performance difference between matched and unmatched modules, though.

Edit3:
To summarize, benchmarks show only a slight difference between matched and unmatched modules because the chipset is doing dual-channel anyway. You will probably never notice the slight decrease in memory speed in real world applications, but you will notice a huge increase in speed from using the hard drive less.
 
matt, thanks for clarifying that for me :)

silly me, i shouldnt have mixed the two.

how can the CPU handle two channels if they both come in at the same time? wouldnt they interfere with each other? or is there some kind of cache/buffer that they are put into?
 
I think the FSB has enough bandwidth to handle it, and dual-channel eliminates a memory controller bottle neck.

I'll use my overclocked desktop configuration as an example.
FSB: 400MHz
CPU multiplier: 8.5
CPU frequency: 3.4GHz (Q9550 quad core!)
Effective FSB: 1600MHz (this would be 800 or 1066 in a MBP)
RAM:FSB ratio: 1:1
RAM frequency: 400MHz
Effective RAM frequency: 800MHz (DDR2-800)

The FSB (Frontside Bus) is "quad-pumped", so it transfers data 4 times per clock cycle. The RAM is dual-pumped, or double data rate, so it transfers data twice per clock cycle. The FSB is 64 bits wide, and each RAM channel is 64 bits wide. So in each clock cycle, the FSB has 4 "slots" for data, and each RAM channel can fill 2 "slots". I think this is where interleaving comes in, basically the channels take turns putting data on the FSB in a single clock cycle, as far as I can tell.

I don't have any expertise here, but this is what I can gather from some quick research. There are a lot more complexities that come into play with all of this (like the RAM:FSB ratio), and once you understand one part you will probably be more confused about some other part, until you understand the entire computer!

Here is some more reading:
http://en.wikipedia.org/wiki/Dual-channel_architecture (not very helpful)
http://en.wikipedia.org/wiki/Front-side_bus
http://en.wikipedia.org/wiki/Memory_divider
 
Sure the laptop can use the 8 gigs. but it will overheat and likely catch fire, bursting the screen and sending glass into your eye socket. Darn that Apple Computer!!!!
 
I'm curious whether anyone has tried the 8GB upgrade on the new polycarbonate unibody macbooks...

OWC seems to claim that they support the full 8GB

However, I'm fairly certain that the white unibody macbooks are unable to access the 64-bit kernel in SL, so I'm a little hesitant to drop $500, if my system is going to become unstable. Has anyone had a chance to try out this combo?
 
LordMelkor said:
I'm curious whether anyone has tried the 8GB upgrade on the new polycarbonate unibody macbooks...

OWC seems to claim that they support the full 8GB

However, I'm fairly certain that the white unibody macbooks are unable to access the 64-bit kernel in SL, so I'm a little hesitant to drop $500, if my system is going to become unstable. Has anyone had a chance to try out this combo?
Click to expand...

Did you ask them that specific question about not accessing the 64 bit kernel? I have found the tech people at macsales/owc to be extremely competent so would probably defer to them. I think they would refund your purchase if it didn't work too.

Steve
 
Hi Everyone,

This is my first post on mac rumors and I would like to let you know my experience with 8gb of ram in a MacBook Pro 4,1 Penryn 2.5GHz.

I purchased g.skill's 8gb (4x2) set of ram and put it in my laptop. Snow leopard was installed prior to this, and would boot into 32bit mode. You have to set it to 64bit mode as soon as you install the ram or even before. Otherwise, the laptop will run extremely slow.

Once you have enabled the 64 bit kernel, then you're all set for snow leopard. I would watch out, though. I tried to update my snow leopard to 10.6.2, but unfortunately never finished, and when it did .. made my kernel panic. Nothing I could do except reinstall.. Bad idea.

Reinstalling snow leopard with 8GBs is frustrating, don't even try it. It has said 7 more minutes for about 7 HOURS. I believe the problem is that the snow leopard install is in 32bit mode and having problems addressing everything. Lesson is, if you're reinstalling, take out one of the RAM sticks

Oh bootcamp you ask about? Won't work with 8GBs. I've tried windows 7 ultimate and windows vista (both 64 bit) and they won't even boot. If they do boot, you just get a black screen with a mouse cursor.

The lesson here is, if you want 8GB you better be content with a) never using bootcamp, b) being weary on updating OS X

Thank you,
Nick
 
LkBurn said:
Hi Everyone,

This is my first post on mac rumors and I would like to let you know my experience with 8gb of ram in a MacBook Pro 4,1 Penryn 2.5GHz.

I purchased g.skill's 8gb (4x2) set of ram and put it in my laptop. Snow leopard was installed prior to this, and would boot into 32bit mode. You have to set it to 64bit mode as soon as you install the ram or even before. Otherwise, the laptop will run extremely slow.

Once you have enabled the 64 bit kernel, then you're all set for snow leopard. I would watch out, though. I tried to update my snow leopard to 10.6.2, but unfortunately never finished, and when it did .. made my kernel panic. Nothing I could do except reinstall.. Bad idea.

Reinstalling snow leopard with 8GBs is frustrating, don't even try it. It has said 7 more minutes for about 7 HOURS. I believe the problem is that the snow leopard install is in 32bit mode and having problems addressing everything. Lesson is, if you're reinstalling, take out one of the RAM sticks

Oh bootcamp you ask about? Won't work with 8GBs. I've tried windows 7 ultimate and windows vista (both 64 bit) and they won't even boot. If they do boot, you just get a black screen with a mouse cursor.

The lesson here is, if you want 8GB you better be content with a) never using bootcamp, b) being weary on updating OS X

Thank you,
Nick
Click to expand...


Hello i have exactly same macbook pro but with 6GB so can you confirm if i bought other one 4gb my macbook pro both on 64bit he work with 8GB?

Thanks
 
Awesome thread. :D Good info!

I'm sure this has been covered already, but I had read that using 8 GB of RAM has caused weird problems with some people's MBP's (and using 6GB fixed it and everything would run fine). Is this still the case? I've been considering putting 8 GB in my Penryn MBP.
 
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