Thinkpads Forum

Does anybody know why I can only see 3 gigs in vista of the 4 gigs of physical ram that I have in my new T60p? Thanks.

That's a hardware limitation of the chipset I believe...others here have discussed it. I don't believe you will be able to get 4GB of ram going until Intel's new chipset, Santa Rosa, comes out. In the mean time, the limit is 3GB and theres nothing that can be done I'm afraid...

Chipset limitation, I think.

You are using a 64 bit OS, right?

mybellyisempty wrote:You are using a 64 bit OS, right?

No I am using 32 bit OS. Should I be using 64 bit OS?

It won't make any difference -- you will still see only 3 GB. If you are running 32-bit XP or Vista, use the /3GB switch in boot.ini to use the max memory (rather than the usual 2 GB for apps).

But I would recommend that you sell one of the 2 GB modules and buy a 1 GB one instead as it really won't do you any good, no matter what the OS is.

tomh009 wrote:It won't make any difference -- you will still see only 3 GB. If you are running 32-bit XP or Vista, use the /3GB switch in boot.ini to use the max memory (rather than the usual 2 GB for apps).

But I would recommend that you sell one of the 2 GB modules and buy a 1 GB one instead as it really won't do you any good, no matter what the OS is.

If you switch to linux you can use memory upto 4GB.

ryengineer wrote:If you switch to linux you can use memory upto 4GB.

Based on tests done by other posters on this forum, it doesn't matter what OS you use -- only 3 GB will be addressable. See this thread:
http://forum.thinkpads.com/viewtopic.php?p=222106

Some more background info here:
http://blogs.zdnet.com/Apple/?p=321

Or have you tested with 64-bit Linux and been able to use the full 4 GB of memory?

tomh009 wrote:Note from Moderator: Snipped overly long, nested quote.

Yes, try Ubuntu you'll get exactly 4gb of ram running. But I just forgot I was on thinkpad forum, thinkpads won't run 4gig due to mobo limitation. Otherwise it is very possible and I've tried it.

I don't understand why do they advertise "Supports up to 4GB maximum memory" when only 3GB of it is actually usable, regardless of the OS.

Why stop at 4GB then? Why not say they support 64GB of RAM when only usable is still 3GB?

ryengineer wrote:Yes, try Ubuntu you'll get exactly 4gb of ram running. But I just forgot I was on thinkpad forum, thinkpads won't run 4gig due to mobo limitation. Otherwise it is very possible and I've tried it.

Sure, with different hardware you will see it. My FreeBSD/amd64 server has 8 GB and all usable, too. But that's really a moot point: ThinkPads' current Intel chipset/Lenovo BIOS implementation will not allow you to access more than 3 GB regardless of the OS.

tomh009 wrote:But I would recommend that you sell one of the 2 GB modules and buy a 1 GB one instead

And do it ASAP, because the prices of 2GB modules will drop rapidly.

I have 1gig in my T60, but depending on whether or not I have to buy a new laptop for my third year at college, I'm going to upgrade to 2gb. It seems with all the stuff the college has running in the background 1 gig isn't enough.

But that does seem strange that IBM would advertise a 4gb limit when the hardware is not capable of recognizing that much.

Miller88 wrote: But that does seem strange that IBM would advertise a 4gb limit when the hardware is not capable of recognizing that much.

If you look closely at the lenovo page where is says that you will find an star, indicating there is an issue. (it is kind of deceptive, though) As others have said the memory limitation is due to the current Intel chipset. It reserves around 512MB for device addressing. So, if you install 4GB, you should see something greater then 3GB, possibly up to 3.5GB depending on your exact system configuration.

So what they are saying is physically it can fit 4gb of ram but it only sees 3 - 3.5gb of it?

Not that I could afford 4gb anyway.

syedj wrote:I don't understand why do they advertise "Supports up to 4GB maximum memory" when only 3GB of it is actually usable, regardless of the OS.

Why stop at 4GB then? Why not say they support 64GB of RAM when only usable is still 3GB?

Because the T60p hardware itself definitely supports 4GB of RAM. My Debian on T60p can use the whole 4GB memory well. As far as I known, memory threshold of 32bit windows is 4GB. I don't know why only 3GB memory can be used.
I don't think that it's the chipset limitation and I cannot find any related information in Lenove's site.

You are seeing the full 4 GB? In 32-bit or 64-bit Linux? That doesn't match what other posters have experienced, though I think they didn't specifically use Debian.

Can you post the relevant bit from your dmesg.boot (first half page to a page or so) so we can see the details?

Shallot.P wrote:

syedj wrote:I don't understand why do they advertise "Supports up to 4GB maximum memory" when only 3GB of it is actually usable, regardless of the OS.

Why stop at 4GB then? Why not say they support 64GB of RAM when only usable is still 3GB?

Because the T60p hardware itself definitely supports 4GB of RAM. My Debian on T60p can use the whole 4GB memory well. As far as I known, memory threshold of 32bit windows is 4GB. I don't know why only 3GB memory can be used.
I don't think that it's the chipset limitation and I cannot find any related information in Lenove's site.

I've used Debian, its not possible to achieve 4gigs on any thinkpad (released till today), no matter what OS (32 or 64 bit) you use.

P.S. Physically you can put 4gigs.

Just as an addition, this limitation crosses all laptop manufacters that use the current intel 950 based chipsets, including the Apple MacBook, MacBook Pro, and some 2006 year model HP business laptops.

Currently, to get around this issue, you either need an AMD based laptop, or a laptop that uses an Nvidia or ATI laptop chipset, which are quite rare, but can be found.

Just so you know, it's not just Lenovo or Thinkpads that suffer from this problem. All the users of the current MacBooks and MacBook Pros are affected (even though Mac OS X is 64 bit)

Despite not being able to address 4GB total - i think it might theoretically run faster with 2GB + 2GB rather than 2GB + 1GB as you would be able to utilise dual channel mode. Its not something i've run any tests on though.

This is a limiation of the current chipet architecture (for all suppliers) and has been around for some time. The 32bit addressing of the memory does add up to 4gig but other system resources such as memory mapped PCI I/O space needs to be reserved at the top of memory address space.

As a side note, I did go the the thinkpad web site and configured a T60p with 4gig and a message in red did pop up to tell me that only 3 gig is usable.

tomh009 wrote:You are seeing the full 4 GB? In 32-bit or 64-bit Linux? That doesn't match what other posters have experienced, though I think they didn't specifically use Debian.

Can you post the relevant bit from your dmesg.boot (first half page to a page or so) so we can see the details?

Oh~
Sorry, I made a mistake. The computer I mentioned is not the ThinkPad.

tomatoeblue wrote:Currently, to get around this issue, you either need an AMD based laptop, or a laptop that uses an Nvidia or ATI laptop chipset, which are quite rare, but can be found.

Can you name those notebooks?

All you need to achieve 4gigs is:

-64 bit processor (like Core 2 Duo Merom, upcoming Santa Rosa, AMD Turion X2)
-64 bit OS
-a capable mobo free of intel chipset limitation.

I am sorry, I am a little confused here. By "Nvidia or ATI laptop chipset," are you referring to the video processor? If so, how would they influence the main processor's access to full 4GB RAM?

No, I'm not refering to the graphics card. Nvidia and ATI have been experimenting with producing full motherboards, ie the entire NForce series of products that are full blown motherboard designs that don't use any intel chips. They licensed the specifications from intel, and are making their own motherboards.

At the present, ATI is touting their xpress 1250 chipset, which supposedly supports up to 16 gigs of ram, but it's pretty exotic stuff, and most manufacturers aren't in the mood to fiddle with a new entry when the product refresh is on the horizon with Intel's Santa Rosa, which will presumably solve the problem.

For anyone who's looking for laptops based on these chipsets (which often support both intel and amd), it's better to get something based on AMD Turions instead of the Core 2 Duo.[/url]

Thank you for clarifying tomatoeblue. I wasn't aware of all this.