4 GB memory, OS or chipset issue?

Is max memory limited by the OS or the chipset? Will Santa Rosa support +4 GB on x64?

 

OS and yes

 

Memory is limited by both the OS and chipset. The Intel 945 chipsets(Napa) for example the T60 could only use up to 3gb(a Little higher then 3gb but definitely less than 4gb even with a 64bit OS. The Intel 965 chipsets(Santa Rosa) for example the T61 can use 4gb with a 64 bit OS.

But depending on your needs 4gb might be overkill

 

What is the chipset limitation on a 32 bit 0S?

 

With a 32bit OS i think you can only use about 3gb(i dont know the exact number) in Napa and Santa Rosa chipsets.

 

Here is a recent thread on this very subject:

http://forum.notebookreview.com/showthread.php?t=133299&highlight=4GB

 

ok

my dilemma is that while im waiting for my T61 to arrive, Im trying to work out whether 4Gb or RAM will be reported as 3Gb or something higher than that. the reason I ask is that my desktop reports 3.58Gb with 4Gb RAM on Vista 32.

If the T61 will only report 3Gb specifically I'll purchase a 2Gb module in addition to the standard 1Gb supplied. If it will report something like 3.5Gb I'll probably purchase two 2Gb modules.

I guess my main question is, will the T61 specifically report 3Gb of RAM or will it report 3.25Gb like the T60 when 4Gb's of RAM is installed.

Thanks

 

buy the single 2GB module. I have (2) 2GB and it reports 3070MB of RAM in Vista 32.

 

32bit OS cannot access more than a bit over 3gb of Memory.

It is a limitation of the way the OS and Chipset work together.

64bit OS and Chipset solve this problem and allow 4gb or more.

 

This is not totally true. You can access a LOT more than 3GB, but not all memory intalled.

At work, we have both Dell XPS and IBM/Lenovo Thinkpad laptops. We choose the T60 models for their compactness/weight and reliability, while we choose the XPS M1710 and M2010 for their 17 and 20-inch screens and somewhat faster graphics chips. The ThinkPad T60 computers have problems accessing over 3GB RAM, and that is NOT because of the chipset or the OS that we use, but, it is only because of the incompetent designers/engineers at IBM or Lenovo; let me explain:

We have tried to install both 32-bit and 64-bit version of Vista, Windows Server 2003 R2 STD, Win XP and different dists of LINUX on T60, T60p, Z61, Z61p, Z61m, (X60 and T43) and Lenovo 3000 series, but they simply can NOT access memory over 3GB (X60 and T43 can not support that since their chipset seem to have accessing issues over the magic 3GB, but we tried anyway)

We also tried the same thing on Dell XPS M1710 and M2010, and they could access almost the ENTIRE 4 GB installed even with 32-bit version of Windows Vista (BTW, 32-bit Vista can access 16 GB RAM with the right chipset so...). Of course, now you can guess that it was no problem with the 64-bit version of the OS:es we tried.

The Dell XPS M1710 and M2010 use exactly the same chipset found in T60 and Z60 series (Mobile Intel 945PM Express Chipset). In December 2006, we even opened a T60p (model 2007 8JG) and compared the chipset with the Dell XPS M1710, and well, I suppose that you have already guessed that it was the same chipset in both machines.

Honestly, I hoped that we would find the Mobile Intel 945 GM or GMS chipset in the T60 laptops (those chipsets seem to have this 3GB limit), since we had a BIG argue with the support guys at Lenovo, and they came with totally silly answers why the computers can not access over 3GB RAM. They even asked me what I need 4GB RAM for!! Can you imagine that?! You can ask ANY programmer/developer who works with virtual machines (both VPC and VMWare or even Parallels) and everyone will tell you that you can not have too much RAM!!! And it IS A BIG difference between 3GB and 4GB. However...

Now, we have heard rumors that HP NX94xx also can access 4GB RAM installed, but I can not confirm it myself, since I have not seen it myself.


And now, regarding to your post about mixing 2GB SO-DIMM with 1GB SO-DIMM, I would not recommend it. The 2GB SO-DIMM memory modules are pretty cheap now, and besides, you will lose a lot of speed mixing 2GB with 1GB memory modules. Just try different benchmarking programs and you will see. If you want to see quick results without a lot of installations, try Memtest86+

However, I think that it is very rotten that IBM/Lenovo does not care about their customers and lets a lot of incompetent technicians answer the phone. I have tried to come in contact with higher bosses and engineers, but they are simply unavailable. But it must be a way that we customers can make them hear us.. I only do not know how! :-/

And so, here ends my first (and long) post in here!

 

My T60 is on the way. I order it with 1GB stick of memory. I'd like to max out the memory. From reading all of this- is it best to jut by 1 stick of 2GB memory for a total of 3 GB? I'd appreciate any opinions!

 

So its a BIOS or hardware issue?

 

Depends on if you are getting Windows XP or Vista, and your needs. If XP, I say 2 GB is enough, if Vista, perhaps 3.

 

Sorry, I'm getting Windows XP Home. I figure, why not Max it out at 3gb? Should I worry about loss of dual channel?

 

I woudn't worry at all.
I have 3GB in mine.
CPUz reports dual channel though.
Must be assymetric...

 

paradoxer,

I'm interested to know if you managed to actually get the OS to say 3.9GB or something of available memory in the Dells you tested. Having 4GB reocgnised in the BIOS vs actually having 4GB in the OS is different, and my HP nc8430 (similar to nx9420, nx8420, etc.) recognises 4096MB in the BIOS, but a 64-bit OS can only use 3.4GB of it, even if 4GB is seen as the physical installation.

Does the T60's BIOS show 4GB when installed?

 

That is exactly what we also noticed on the HP, but on the IBM T60 models (and all ThinkPad models with the Mobile Intel 945PM Express Chipset) the memory above 3GB just does not seem to exist! Dell XPS machines report 4GB RAM, even in 32-bit Vista, but through some tests, you will notice that the actual free memory is less than 4GB (it also depends on which OS you use, and they report different amount of RAM available)

The BIOS shows that it is 4GB installed, but it does not seem to report more than exactly 3GB to all OS:es we have tried with on the T60 series.

When the OS boots up and is running, it handles the calls for reading and writing to the RAM by itself, and if we want to read and/or write to a specific area in the RAM, the only way is to do it before the OS loads. Here is where we try to access the memory above the 3GB, but for some reason, ThinkPad laptops just seem to have "lost" that gigabyte over 3GB. Unfortunately, we do not have any knowledge about the BIOS and the embedded controller software, but I think it is the BIOS which capps the memory.

But of course, I accept that the installed devices in the computer steal a lot of memory, but it is not as much as 1GB. Neither do I accept the fact that IBM/Lenovo sell computers with 4GB preinstalled memory, but you can not access more than 3GB. And it gets extra irritating to see that for example Dell and HP can solve this matter much better than IBM/Lenovo. They do not give you the whole 4GB, but I would be happy for those few extra hundreds of megabytes, since it will make the computer to swap less to disk. If the support staff was not so incompetent, they would report all problems regarding this issue, so the press would be so high on IBM/Lenovo that they _would_have_to_do_something to keep their faces (and make their customers happy)

 

Another irritated z61p owner here.
this has to be addresed since 64 bit computing is slowly gaining speed and becoming the viable option for gamers/sound/video editors/programmers and anyone who needs more out of hes rig.
since the limitation is in hardware/bios config theres no real reason to switch to x64 OS yet , youll get the same amount of accessable memory minus device driver support.
i intend to call my local support representetive in my country until i get an honest answer why such a capable company keeps customers underpowered by defualt.
i want my extra GB now!
will update soon
i urge whoever has the same problem to do the same our power as a computing community will only work in numbers and untill something changes we have to make the change ourselfs.

later

Kilgore

 

No x86 OS can support more than 3. something GB. Where did you come up with 16GB? I'll give you a higher number, let's say...64GB, why not 128GB?
If you want to use more than 4GB of RAM get an x64 OS.

 

"No x86 OS can support more than 3. something GB."

Windows Server 2003 does.

 

No, not really. It uses PAE to recognize more than 3GB (up to 64GB under S03, not sure under S08). Another limitation with Windows is that no application can use more than 2GB of RAM under an x86 OS.
x86 with 4GB of RAM is like a slow car. It's obvious that it woun't go fast, but you still want to spend the money, even if you can get a faster one for the same dough.

 

The latter half of your statement is correct.

But the point is that windows 2003 x86 can reference more than 3 GB regardless of how it is referenced.

 

Yes, but I believe it doesn't work as simple as that. You're scratching your right year with your left hand...

 

http://support.microsoft.com/kb/283037

 

Yet, that's still scratching your right year with your left hand...
/PAE doesn't always work. I have read many comments about it and among those people claimed it didn't work. Get x64!

 

I have x64.

I was simply correcting an error.

 

I know, but hey, this technology is such a pain in the ass when you have an alternative.

 

I agree.

 

a 32 bit OS can have 4GB addresses, and that's all. Now in those addressed the OS needs to map the devices that are installed in your system, such as lan cards, video cards, modem, wireless, etc. The OS uses the memory mapping method for them peripherials, which take address space. So if you have 4gb RAM, then it will be all accessable if you have nothing else ... like a CPU and RAM, lol. And because that's not the case, the OS (or motherboard, I'm not sure) overrides the upper addresses where there's RAM installed with the addresses for the other stuff installed in your computer, so you end up seing less RAM.

I can explain that there's a benefit of having 4gb RAM in a 32bit system because of the video ram, but I gotta go now, will explain later

 

There is a benefit, but you can't use it all properly.

 

It's been asked before on the boards but i couldn't find it in a search. On my quadro 570...it uses some of the system memory...if i were to put 4gb in (not now but i may do it a few years down the road)...would my 32-bit system recognize the extra gig for my my gpu or not...?

 

Let me put it this way: get x64! You can do it for free (with a Vista Anytime Upgrade disk).
You put 4GB only if you want to use x64.
Vista SP1 (x86) sees 4GB, and sticks to seeing, not using it. But yes, it will recognize 4GB. I can see a Ferrari too, but I would also like to drive one.

 

OK, let me finish what I started.

so as I said, if your system is 32 bit then it can work with addresses from 0000-0000 to FFFF-FFFF, or in other words 0 - 4GB. Now, the memory mapping method is one that lets a device to be accessable when the CPU refers to a memory address, which means that this device takes over that memory address. As I said before, almost all peripherials are memory mapped in the upper region of the address space, becaues the system uses the lower addresses for RAM. It could work the opposite, but that's not important (and is not the case anyways)

now you install 4gb of RAM, so you make the conflict of having more deviced than the OS can handle. Look at it like every address could be a different device, so there are a total of 4 gig "simple" devices possible. So something has to give up, and this something is part of your RAM because it takes all the address space anways.

so to make things somewhat clear, Windows says: I'll use upper 1GB or so for mapping devices, and the lower 3GB for RAM if present. Actually the limit is about 3.12GB or so, selected by Microsoft people, which is what you get at the end as usable RAM.

in this scenario, the interesting thing comes with the video card, which takes most of the space in that upper 1GB. The thing is that the memory of the video card gets memory mapped as well, or in other words in order for the system to recognize and use those say 128MB of video memory (in my case), those have to take 128MB of addresses from the system, or would lower eat up 128MB from the upper 1GB. Now this is only for the onboard video ram, but the video card has GPU which is supposed to receive other commands, so those are memory mapped as well, or a card with 128MB video ram will take a lot more address space than 128Mb (I think about 170MB, I'll explain how I came up with this number below).

now, my video driver reports 512MB of video memory. This means that 512MB of address space are reserved instead of 128MB, and that's in the upper 1GB. Or even if take into account the GPU commands as well then that would be about 700MB. So Everything works fine, you've got 3.1GB RAM, 512GB video ram, and other devices that take the rest 200MB or so from the upper space. In most cases you've got some free address space in the upper 1GB for other devices that you may install in the future.

But what happens in the case if you have 3GB RAM installed, instead of 4 .. Well, those 384MB of video ram get relocated where you actually have RAM installed, so you end up with less than 3GB RAM or that would be about 2.6GB. The system still reports 3GB because those 384MB video ram may not be used, so that would be like application dependant thing. Like if you play a game that requires lots of vido memory, you end up having 2.6gig for the game itself, but if you have a big spread sheet then you have 3gb for it.

I have 2gb RAM. I see that my video card uses about 300MB in the upper 1gb, so since I know that it has 128MB then the rest should be for the GPU and what not. If you want to see it yourself, go to Device Manager, click View and select Resources by type, and the expand the Memory tap. This is your OS in addresses. I added all address space that is taken by the nVidia card, and it came up to be about 300MB.

I believe people with 4GB RAM will also see about 300MB taken out for the video card, but when those 384MB are needed then they will be taken out from the upper 1GB and you'll still end up having 3.1 GB RAM available ... That's the benefit of 4GB vs 3GB RAM.

(my longest post ever, lol)

 

devices that dont get memory mapped are the paralel port, the ps2 port, the serial port. Those have direct I/O channels.

the thing with the /PAE switch is that it allows additional addresses to work with a 32bit system. That happens with the buffering method. It works as follows: say you have to access address that is 64bits (now that's a lot, like 18,446,744,073 GB - yes, gigabites), - then you could send two times of 32 bits so that you can build up a 64 bit address. All you need is a device that can memember the first 32bits that you send for one cycle, so that you can use the 32bit bus to send the other 32 bits on the next clock cycle. This is called double buffering, but you can have tripple and so on buffering as well, just to give you an idea of how much you can do if you wanted, lol.

Well, that device cant do 32 bits with the /PAE switch, but it can do 4 bits, so you end up with a 36 bit address, or 68GB in space. This device could be a software driver. So what this switch does, if supported, is that it can move the upper 1GB in the 32bit OS above the 4th GB address, and the 4GB RAM that you have installed could become all usable. Well, not all drivers like that, or in other words those may expect to receive 32 bit address but they receive a 36 bit address instead, so they crash. That's why you have drivers for 32bit OS, and drivers for 64bit OS for example.

hope that helps somewhat