T410 and memory

[Main Target]

So I was wondering the performance implications going from 2x2GB to a single 4GB module. Anyone have information on this?

[ZaZ]

There's little practical difference.

[wolfman]

For what it's worth, if you were going to grab a 4gb stick why not just add it in with one of the 2gb sticks you already have? I just got a T410 yesterday and added a 4gb stick to the 1x2gb stick I got from the factory...

[w0qj]

The main issue is future expandability.

~Win7 32-bit can only use something like 3.2 GB RAM (can someone pls confirm this value?)

~Win7 64-bit Pro can use much RAM, only limited to your 2 RAM slots and what RAM is available on the market.

a) Therefore if you're using Win7 32-bit, you might as well have 2x2 GB RAM for total 4 GB RAM in both slots (somewhat cheaper this way).

b) BUT if you are using Win7 64-bit (or plan to upgrade to this in the lifetime of your current Thinkpad T410), suggest you buy 1x4 GB RAM (ie: only 1 slot occupied by 4 GB RAM, the other slot remains free for future RAM expansion).

[ZaZ]

Yes, any 32 bit OS can only use 3GB or so of memory.

[dr_st]

Yes, any 32 bit OS can only use 3GB or so of memory.

Technically, 4GB, of which some will definitely be mapped to devices, leaving one with ~3GB usable.

The 4GB limit in 32bit versions of Microsoft's home operating systems is an issue of pure licensing though. For those interested in hacking, it can be removed, at least in Vista/7, with an unofficial patch to the PAE kernel, see my thread here:
http://forum.thinkpads.com/viewtopic.php?f=8&t=93291

[ThinkRob]

Yes, any 32 bit OS can only use 3GB or so of memory.

Any 32-bit version of Windows.

Linux (and I believe OS X) will quite happily support up to 64GB on a 32-bit chip (or a 64-bit chip running a 32-bit kernel.)

[dr_st]

It appears that Microsoft's article (at least its latest version) actually discloses this situation almost openly and clearly:
http://msdn.microsoft.com/en-us/library ... 85%29.aspx

Devices have to map their memory below 4 GB for compatibility with non-PAE-aware Windows releases. Therefore, if the system has 4GB of RAM, some of it is either disabled or is remapped above 4GB by the BIOS. If the memory is remapped, X64 Windows can use this memory. X86 client versions of Windows don’t support physical memory above the 4GB mark, so they can’t access these remapped regions. Any X64 Windows or X86 Server release can.

X86 client versions with PAE enabled do have a usable 37-bit (128 GB) physical address space. The limit that these versions impose is the highest permitted physical RAM address, not the size of the IO space. That means PAE-aware drivers can actually use physical space above 4 GB if they want. For example, drivers could map the “lost” memory regions located above 4 GB and expose this memory as a RAM disk.

[Colonel O'Neill]

Isn't the execute instruction pointer on the CPU when running in 32-bit limited to 4GB? That would mean only data could be loaded into the unmanaged region of RAM.

[ThinkRob]

Isn't the execute instruction pointer on the CPU when running in 32-bit limited to 4GB? That would mean only data could be loaded into the unmanaged region of RAM.

PAE. Applications' virtual address space is limited to 4GB. The big advantage of PAE (and the reason that it's still very useful) isn't that it allows an app to use more than 4GB, but rather that it allows all software to collectively use more than 4GB -- and the latter is a lot more common than the former, at least on a modern desktop.

Yes, Windows is limited to 4GB even on systems that support PAE, but they're the outliers.

[MrPeter1985]

I'm guessing (Main Target) is wondering since you have the option of choosing 2x2g sticks or a 1x4g stick when ordering a T410 online. (which I noticed myself yesterday of that option, for the same price even) So unless you need more than 4gigs down the road. The 2x2g option maybe better for you, as it may have a slighter speed improvement being dual channeled. My 2 cents

[ThinkRob]

Honestly, the performance difference is minor enough that I'd go with whatever is cheapest.

Put another way: if your workload is such that the performance is *that* important, you're the sort of person who's going to upgrade the laptop to 8GB immediately upon receipt.