4gig 2gig question? 32bit 64bit question?

If i get a laptop with 4gig ram, am i just better off with just purchasing it with 2gig ram to acquire dual channel? The laptop i plan to purchase comes with Windows Vista Business 32 bit.

Is there a big difference, bug wise, compatibility wise between the 32 bit and 64 bit OS?

 

Hi turrdrop_88

I'm not sure as to the dual channel question but there is an issue with 4gig of RAM relating to your other question. A 64-bit operating system is required to take full advantage of 64-bit features, including high RAM capacities. A 32-bit OS can only handle 3.2gig of RAM max. The rest of your 4gig wont show up without a 64-bit OS. 64-bit OS's use a 32-bit emulator, just like Windows now (not sure about vista) has a 16-bit emulator for really old programs so it shouldnt cause any compatibility issues.

Grand Admiral

 

Er, what? If you get a laptop with 4gig ram, you have a laptop with 4gig ram. What does 2gig have to do with anything?

Anyway, if the question is whether you should get a laptop with 2 or 4 gigs of ram, the answer is 4. Especially for Vista, 2GB is a bit on the low side.

Nope. Both work fine in 99% of the cases. 32-bit still has better driver support, but in most cases, it's not a problem on 64-bit.

Compatibility-wise, there are two things to keep in mind:
1: 64-bit requires separate drivers (see above), as well as all OS-level applications, that is, firewalls, antivirus, CD/DVD emulation (daemontools and such). Not all firewalls in particular, exist in 64-bit versions.
2: 16-bit applications won't work at all. That is, DOS or Windows 3.1 applications won't run. Not that I expect you to have a lot of them, but it's worth mentioning.

Not entirely true. Even when running 32-bit apps on a 64-bit OS, you'll at least get the full 4gb of RAM available in the OS. Which is nice, when you paid for 4GB.
There are also some other fringe benefits, so if you have the option (And your hardware is supported, of course), there's no reason not to run a 64-bit OS.

 

so it owuld just be ok to purchase 4gig ram and use a 32 bit OS?

Lastly what are examples of 64bit apps? does this include adaware? avg? advanced windows care, etc etc

 

how would i know if a app is 64bit anywayz?

 

If your OS is preinstalled with a 32 bit OS, it is very likely that the BIOS will not allow the OS to fully utilize 4GB RAM, even if you replace the OS with the 64 bit version. More likely that you can only use 3 out of 4GB RAM.

I am not aware of any laptop which hardware allow you to fully utilize 4GB RAM. If anybody knows any, I would be very interested to see the spec.

 

yes, you can go ahead and buy a laptop w/ 4 GB ram and use 32 bit programs. As already stated, all drivers must be signed under vista 64bit, or they don't work. To find out if a manufacturer makes their program available in 64bit, go to their home website and check out each program. You can also "goggle" for Vista 64bit" compatible programs.

But if you install Vista 64bit, remember, it is an upgrade, so save all your files, documents, etc, before installing it. Also, be aware that when installing vista 64bit, YOU MUST BOOT from the disk, you cannot install from any 32bit OS to Vista 64bit. Plus, some SATA drivers may need to be inserted during the install sequence, so have them ready. Same for chipsets. I highly recommend going to your manufacturers website and downloading all the Vista 64bit drivers for your laptop in advance of the install. You're also going to need drivers for printers, sound cards, video cards, etc. And some BIOS will crash/die/blue screen if you have more than 3GB ram during install, without the proper flash updates.

First off, make sure your system is ready for even vista 32bit, by going here http://www.microsoft.com/windows/pr...pgradeadvisor.mspx?wt_svl=20409a&mg_id=20409b and downloading/installing the program.

good luck!!

 

They all say "64bit" on them when you download, etc... You really don't have to worry about this. You do not need "64 bit apps" to run a 64bit OS. Any 32bit or 64bit program will work for the most part. Others who say that you need to have all 64bit apps are incorrect.

Not even close. Any/all laptops sold today that are 64bit capable can address 4GB of RAM. The BIOS is only a small player, but if the laptop has a 64bit CPU, there's a good chance it will support 4GB. There was a small transition period where this might not be true, but that was over a year ago, so anything new will definitely support 4GB.

The other limitation is the OS. You can only see 3.2GB with a 32bit OS, so that might be what you are referring to.

 

Look at the complain that others have been saying in this board about their system not being able to see all 4GB RAM, even with a brand new 64 bit computer, even with a 64 bit OS. Even the latest Sony SZ6xx series can not fully address 4GB RAM. Just take a look at the BIOS, it will say that only 3GB RAM is available.

The BIOS has the final say. It's the final decision maker. So, if you have 4GB RAM installed and you go to the BIOS and the BIOS say all 4 is available to use for the system, then you are OK but I have never seen any laptop like that.

Most newer system today do support 4GB Memory Address space, but this memory address space is for all hardware installed in the system, not just RAM. The memory address space that has been reserved for other hardware in the system can not be used for the RAM. So, if you have 4GB RAM, and your other hardware need 1GB memory address space, your RAM can only use 3 out of 4GB.

Now, does it mean that if you have 2GB RAM, then you can only use 1 out of 2GB, because the other 1GB has been used for the hardware? The answer is no. That is because most hardware only use the highest upper memory address space. So, if you only have 2GB RAM, you can use all or nearly all of the RAM because the RAM use the memory address space between 0 to 2GB, while the other hardware use between 3 to 4GB memory address.

 

I am fully aware of how address space and memory work together. ALL 32 bit architectures support 4GB address SPACE, that's the definition of a 32bit system. It's also the reason why 32bit OSes can't see all of it. You are correct that it is because some of that space is reserved for device mapped IO and shared communication channels.

If the BIOS is not seeing the RAM, then it is because there is a problem in the BIOS or the chipset does not support it. Any new laptop with the Santa Rosa chipset will be able to use 4GB of RAM, period. Maybe I didn't qualify that enough and assumed that new systems would come with that chipset. Even the older chipsets can support 4GB of RAM, if they were wired correctly. Some systems were not wired for it to save some money.

I am running a laptop right now that has 4GB of RAM, and so are many others. To say that they don't exist is purely farcical. Maybe you personally have not seen one, but that probably because you haven't been to a computer store lately.

I think you have a firm grasp of the ideas behind how memory works in the system, but your assumptions and conclusions are 2-3 years out of date.

 

Sony SZ6xx has Santa Rosa chipset, but if you take a look at the BIOS, it only sees 3 out of 4GB RAM. Price wise, the Sony SZ series is at the higher end so I don't think Sony does it to save money.

 

Despite what some posters have said, 2Gb works great for Vista 32-bit.
I type this on a very peppy machine for Vista that "only" has 2GB...

Make sure to grab the hotfixes for Vista if your version does not already have them:
Compatibility fixes - KB938194
Memory - KB940105
Performance - KB938979
Stability - KB941649

These made a very large difference in performance for me.

Note: all of these I would expect to be included in SP1, but there are no guarantees.


All 32-bit OSes are limited to 4GB of address space, but total address space and address space available to system RAM is not the same.

This is especially true in Windows (Xp as well) which has single-application limits of 2GB as well as only allowing certain types of system RAM to use 2GB address spaces. (its not actually ONE 2GB limit, its a couple)
Windows has TWO types of addressable memory types.
User Mode (only to that program) and
Kernal Mode (all programs)

Both modes get 2Gb of addressable space, note that that does not necessarily mean those addresses correspond to hardware.

Note that you are using address space under than 4GB for things like:
-Video Adapter RAM
-Other hardware address space (some motherboards)

Indeed before the memory hotfix I listed above, you were addressing your video RAM twice.

Example:
Let's say post-hotfix, you had a 512MB video card and your motherboard hardware reserved 512MB of addresses. Grats you on 3GB MAX of addressable space. (typical is actually 1.2GB or so of address space eaten by video and other hardware)

Let's say the above was true and you only had 2GB of RAM.
You have plenty of addresses for your hardware and the 2GB limits on user mode and kernal mode match the size of your RAM anyway. Your computer happily swaps out RAM for virtual RAM when it needs more.

Let's say you upgrade to 4GB.
You now have only 3GB of your hardware that you can even begin to address. Add on top of that windows will only address up to 2GB for either user mode or kernal mode and thus the 1GB over the 2GB will not be used nearly as efficiently as the first 2GB. Of course, multiple applications will see better performance and even single applications + windows wil be better off with the extra GB to play with, but it isn't the same as the first 2GB due to windows' limitations. The upgrade will see a performance increase, but it may very well not be worth the money pricewise right now. (2 x 2GB sticks have a price premium right now)

In short:
-Will Vista run "well" in 2GB?
Yes... almost as well as you will see with 4Gb of hardware memory.
-Will 4GB see higher performance? Yes, but not by as much as most people are expecting with the cost of 2GB sticks.
-Is the extra memory "worth it?"
This is really in the eye of the beholder. For me? Not yet. More RAM is better, but not worth the price tag of upgrading from 2 x 1GB to 2 x 2GB.
-If someone was puchasing now, would 4GB be worth it?
Again eye of the beholder.. Some applications need every scrap of RAM they can get and even with Windows' limitations, it might be worth it. Gamers have reported slight performance increases, but most are dissapointed. Graphic programs and those who keep mulitple copies of layers (picture/video editing/3Dmodeling) might very well see benefits that are worth the price tag.