Windows 7 32 bit vs. 64 bit? In this first part of a comprehensive series I discuss how 64 bit and 32 bit Windows 7 differ with regard to performance and memory.

In my last post, I described my experiences with Vista x64. Today I will focus on two important topics related to the Windows 7 64-bit vs. Windows 32-bit controversy: memory and performance.

Memory ^

The most significant advantage of a 64-bit system is that it can use more than 4GB of RAM. One thing that has changed since I last concerned myself with this topic is that most new desktops and laptops now come with at least 4GB of RAM. The problem is that like Vista, Windows 7 x86 is capable of only using about 3 GB of RAM. By contrast, Windows 7 x64 cannot only make use of up to 16TB 192GB RAM, but is capable of using the memory remapping feature of modern BIOSes, which allows the operating system to really use the complete 4GB. Thus, if you install Windows 7 64-bit on a 4 GB machine you won't waste 1 GB of RAM like you would with Windows 7 32-bit.

Microsoft-64-bitMoreover, it is only a matter of time until 3GB will no longer be enough for modern applications. One example is Windows 7's XP Mode feature, which allows you to use legacy applications within a virtual machine running within Windows XP. This feature might prove to be useful for other purposes, for example running Office 2007 and Office 2003 on the same computer simultaneously. Since XP needs 512 MB-1GB to run properly, XP Mode is a RAM eater. As such, if you now deploy Windows 7 32-bit then you might be soon want to move to 64-bit, just because you will have to upgrade your machines with new memory. My own laptop has 8 GB of RAM and I can tell you that I need every byte of it. I’m lucky that my laptop supports up to 16GB.

Performance ^

In a previous article about Vista x64, I outlined how the 64-bit version will usually only perform better as it allows you to use more memory, rather than because of its computing capacity. Only applications that are optimized for 64-bit will run faster than their 32-bit counterparts. There are now significantly more 64-bit apps out there than a year ago, but don't make the mistake of thinking that they will be faster than their 32-bit counterpart. Usually, there is only a special 64-bit edition because the 32-bit version wouldn't run properly on a 64-bit Windows OS.

This is different only for some performance-dependent application types, such as mathematical software or video editing programs. Hence, if you have software whose vendor explicitly endorses 64-bit, then you might notice improved speed with Windows 7 x64.

On the other hand, Windows 7 64-bit won't slow down your computer. There might be a little overhead in some computations because it logically takes longer to process 64 than 32 bits. However, in practice you won't realize the difference. All performance tests I've seen prove that in most cases there is simply no noteworthy difference between 64-bit and 32-bit when it comes to performance.

However, this might soon change. There is no doubt that the future belongs to 64-bit. More and more software vendors will offer special 64-bit editions of their applications as time goes on. The most prominent software will be Microsoft Office 2010, which will also have a 64-bit variant. It remains to be seen whether Excel or Access will perform better in 64-bit.

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In the next article of this series, I will cover Windows 7 64-bit’s software and hardware compatibility.

  1. Paul 11 years ago

    I have a 3GB laptop was running Win7 x64 straight from the shop. A year on I needed to re-install windows, I had both x64 and x32 copies, with the x64 disk not working, i have found that x32 runs loads smoother and well within the system resources. Is it safe to say that if you’ve got less than 4GB, always opt for x32?

  2. Arubi Lucky 11 years ago

    I have a Window 7 (64 bit) Laptop and a Window Vista (64 bit) Mini Tower Computer but having some problems running some of my applications, a 32 bit application. So how do I make it work even on these Computers.

    I copied a folder containing a FoxBase + from a 32 bit Computer to these my 64 bit Computer but would not work

    Can I also have any FoxBase + program that can run on 64 Bit Computer from anyone please

  3. sebi 11 years ago

    i have been using w7 hom basic for ma dell inspiron lap 15.6″. recently i instaled w7 ultimate 32-bit. it shows som variation in my display. it is not like as it before.
    is there any variation in the display of 64 & 32 bit.
    i dont have the dell drive disc . the function keys were not working properly..!!!
    and the sleep option seems desabled.

  4. Marcelo Cantos 11 years ago

    The theoretical address-space limit for a 64-bit architecture is not 16 TB, it’s 16 EB, or, more accurately, 16 EiB (2⁶⁴ = 2⁴×(2¹⁰)⁶).

  5. y0man 11 years ago

    y0! just install e.g. server 2003 32bit on a 4GB machine and see, how much it uses without any tricks.. just for info… why should 32bit not be able to use 4GB ?

  6. A1D4N 11 years ago

    Ok the bit that I dont understand is, by what I have read a 32 bit system can handle at a max up to 4gb of ram where as a 64 bit system can handle wayyy more due to the amount of revolutions of the processor? But if a 64 bit system can handle a significan amount more than the 32 bit system why do they sell some of the 64 bit systems with only 4gb of ram, is this not just restricting them to the same as the 32 bit??? Im trying my best to understand any help ould be greatly appreciated. :’)

  7. A1D4N, actually 32-bit systems usually can only handle 3GB and as I have outlined in this series, 64-bit has other advantages.

  8. A1D4N 11 years ago

    Michael Pietroforte, yes I have read that, I have been reading various forums and websites on the matter and that has come up quite a bit but hat im stuck on is the fact that say 32 bit systems only use 3gb then you are waisting 1gb of ram but 64 bit machines can handle upto 16eb? now no computer is sold with 16eb of ram so is a 64bit computer with say 4gb of ram limited to 4gb instead of the 16eb it is capable of?

  9. How much RAM a PC can use depends not only on the operating system, but also on the motherboard. You have to ask the PC vendor how much memory the machine supports. Most PCs can be upgraded to more than 4GB. The reason why PCs with 4GB are sold with Windows 64-bit is because you would waste 1GB with Windows 32-bit.

  10. johne53 11 years ago

    Interesting to read the comments from people who upgraded to Win64 and then found their machines running slower! I’m guessing they probably carried on using their old 32-bit apps after the upgrade. Some programmer colleagues and myself are working on a Windows app (currently 32-bit) and have noticed how sluggish it is when run on Windows 7 64-bit. We’ve spent months trying to find a reason for this in our own code but can’t find anything. Presumably Win64 needs to emulate a 32-bit VM for running each 32-bit app. From the tests we’ve done, the emulated processor seems to be roughly equivalent (performance wise) to an old Pentium IV or AMD Athlon etc from about 10 years ago. i.e. 32-bit apps will run but not necessarily very well. I don’t know if it’s possible to ‘tweak’ the VM performance but I’d be really interested to find out.

  11. Marcelo Cantos 11 years ago

    32-bit software doesn’t run virtualised in a 64-bit OS. There are some performance penalties associated with accessing 64-bit OS functionality via some kind of adaption layer, but the penalties are quite small. A sizeable chunk of OS functionality runs in user space, for which 32-bit versions of the system libraries are available, and kernel-level functions go through an adaption layer for all processes, not just 32-bit ones.

    Note in particular that MS Office runs 32-bit even on a 64-bit OS (there is a 64-bit Office, but almost no one installs it due to some significant limitations vs the 32-bit version). I run 32-bit Office 2010 under 64-bit Windows 7, which is itself running in VMWare Fusion on my MacBook Pro notebook. It starts Excel in under one second. I generated some data and got it to plot a graph of four thousand data points with lines and markers, then resized and moved the graph around. So far I haven’t been able to measure the time it takes to do any of these operations. They are effectively instantaneous. Microsoft would be skinned alive if Office regressed to ca 2001 performance.

    There are some performance implications due to the larger size of pointers, which also makes lookup tables and other kernel data structures grow in size, which in turn hurt cache locality. But again, the difference should be imperceptible to most real-world users.

    By far the most common cause of performance issues on PCs in the real world is lack of RAM. Most of the complaints above seem to involve machines with 4 GB RAM or less. That really isn’t enough these days. Even 32-bit systems are at the threshold of pain running modern OSs and software. 64-bit systems, being just a little bit more memory-hungry, tend to push these systems over the edge. Get more RAM. 6 GB should be the minimum, with a preference for 8 or 12. Alternatively (or in addition), switch to an SSD; due to the negligible seek times, this will dramatically reduce the cost of paging when RAM is exhausted.

  12. handa fanda 11 years ago

    i would wait till all my programms offically support 64 bit os as simple as that

  13. Leevy 11 years ago

    No one actually mentioned why is 32 bit OS limited to only 3 GB of memory, I mean can’t someone just write a hotfix or something ?

  14. Leevy, actually someone mentioned why Windows 32bit is limited to 3GB. 😉

  15. Jack McCarty 11 years ago

    I purchased a used 3DBoxx from a graphics artist w/ Vista Ultimate 64-bit running (but kinda shaky) and decided to upgrade to stable Win7 Ultimate. The system on Vista was showing all 18GB of RAM useable. When I upgraded with a clean install (it’s complicated…that was the path travelled) to Win 7 Ultimate 64-bit, only 3GB is useable. The upgrade was a costly mistake if I can’t get the existing installed memory all working as a team. How do I harvest all that sweet memory that I saw working on Vista 64-bit?

  16. MagicAndre1981 11 years ago

    Load the default BIOS settings and also make sure that you don’t limit the RAM with msconfig to 3GB.

  17. geebs46 11 years ago

    Great article and posts – and sorry if I’ve missed something obvious 🙂 I’m soon receiving an on-line purchase viz an i5 processor c/w 8 gb ram. If I choose to install 32 bit version of windows 7, will 5gb ram be wasted (or will the processor be thankful I bought extra ram on the basis that some software eg speech recognition works best with plenty of ram)? BTW if the future is 64 bit, I’m not exactly seeing positive posts above!

  18. geebs46 11 years ago

    Hey re my post #68, I think I’ve actually managed to unravel the issues – ‘found the link below that essentially seems to indicate there will be no problems running 32 bit programs on my likely implementation of the Windows 7 64 bit o/s that will access/make full use of the 8gb ram I’ve ordered. I assume that 32 bit software with an i5 cpu is all gonna work pretty fast 🙂 Best

  19. Bobby 10 years ago

    3GB hotfix LOL!!

    I am actually surprised that you are not mentioning the architecture issues involved in using 32bit programs on a 64bit OS. Pretty much, a 32bit program using 1GB of memory in a 32bit OS will consume 2GB in a 64bit OS. So if you are just using 32bit program thats pretty much all of them today and you have 4GB of RAM you are better off using a 32bit OS and use 3GB than using W64bits and getting only to use 2GB!!!

  20. Marcelo Cantos 10 years ago

    @Bobby: If a 32-bit process asks the OS to allocate, say, 512 MB of RAM, why would a 64-bit OS hand over double that amount?

  21. black boricat 10 years ago

    laptop or notebooks has a limitation in putting RAM, thats why when you put a 2x 4gb(8gb) ram, sometimes they read only 4gb, it depends on the brand manufacturer,

  22. Alex 10 years ago

    Well, as for the “Performance” you have stated that 64-bit applications fare better than their 32-bit counterparts. I am sorry to say, that really depends on the developer doing the coding and what tools / compilers and linkers they use. Sometimes the 64-bit applications are worse in terms of speed.

    I know this because I am an electrical, electronic and software engineer. I’ve seen my share of doozies on a 64-bit OSes when applications are written for 64-bit only.

    A note about the way Intel and AMD x86 machines are created along with their chip sets. The 32-bit address space is in fact 4 GB RAM maximum, however it will vary on how much of the RAM is usable because of inefficiencies in the hardware chip sets they use. Some will have better support for more memory than others. There is another part to chip sets many people don’t know or talk about. Some chip sets in the BIOS will allow you to take certain devices off the memory mapping which will allow you to gain more RAM in certain situations.

    For example, you have say, Windows XP Home 32-bit and you have a Gigabyte GA-MA78GM-US2H version 1 motherboard with 4 GB RAM installed, set at 512 MB RAM for video. Currently, you will have a max of 2.75 GB RAM usable showing but there is an option in the BIOS that allows you to switch the 512 MB of RAM for video above the 4 GB RAM barrier, now that works in 64-bit OSes but does something very interesting in a 32-bit OS such as the 32-bit version of XP, Vista or 7, it will get drop in the area of the RAM you can’t normally see with the OS, it gets remapped. So it then will show as 3.25 GB of RAM that is usable while the system is still 100% functional, with no problems. There are little tricks you can use for certain motherboards to eek out little bits of RAM here and there for a 32-bit OS like XP, this works for Windows 2000 as well, if you were curious.

    As it stands, most people don’t understand how memory is addressed in a computer in 32-bit let alone 64-bit mode. This harkens back to the days of expanded and extended mode addressing of memory.

    Expanded memory model means that memory is directly addressed and is not paged, you can see the full 4GB or what ever is installed. You need a 64-bit system and CPU to install more than 4GB RAM however (in the case of AMD / Intel).

    However, the way in which things worked in the newer Intels / AMDs and to have the different modes on the processors work well with each other; Virtual, Real, Protected and other modes, they had to use paged memory addressing aka extended mode addressing. It depends how each chip set would implement the ability of using extended mode addressing, it’s not just a CPU thing in this case, unfortunately (it would be so much easier if it was). Also, it would also have to do with what options they were putting in their chip set and whether or not a PC manufacturer was going to implement all those features or find a way to shut those options off to gain a little more RAM. Some of the older chip sets would not allow you to disable parts or features, it’s was either on or off and as a fixed memory map.

    Now, I will address the speed of RAM vs. more RAM. The speed of RAM like the speed of the CPU and now the GP-GPUs can have significant impact on frame rates of games. Coupled with the fact that not many memory designs are all that great to begin with. The idea of double or quad rate data RAM sounds great but really it’s not. The industry is actually cheating and getting away with it.

    For example, the data is double data rate but does that really mean? It’s double the data rate than single data rate RAM but that applies to read or seek only not writing, if they were to implement writing cycles to be at the same speed as reading, you would see a huge difference in the way your computer operates. Also, the speed at which the RAM addressing occurs is the same as a single data rate vs. double date rate. When I say addressing, I mean the decoding of an address in memory, not the actual data itself. If they doubled that, in addition to double data rate for read and write, that would be tremendous in terms of performance. However, it’s not.

    The reason why people don’t get very good performance in general from DDR series RAMs is the way they are designed and constructed. They are designed to give a moderate increase in performance while fairly easy to construct on the assembly lines in the RAM manufacturing companies.

    There are other DRAM like methods and designs that can give a lot more performance per Watt, such as the Rambus XDR and XDR2 series RAM chips. However, chip set manufacturers would have to retool completely to gain the speed available in those chips.

    Now, I will talk a bit about the mathematical software, people seem to think that by doing everything in 64-bit operands in machine language / assembly that their equations will magically (er logically and arithmetically) be way faster than their 32-bit counterparts which just isn’t true all the time. There is a lot more problems on a 64-bit processor than on a 32-bit, also if you host a 32-bit application on a 64-bit processor you have more problems. I’ve written both 32 and 64-bit assembly language programs in sufficient complexity that do vector mathematical calculations and other complex subjects for near real-time simulations. Some data is just better to be left in 32-bit instructions because of the timing issues with the 64-bit instructions.

    If you are on a fully 64-bit system, meaning only does 64-bit, the BIOS is written in expanded mode addressing, the OS is written in the same way and you don’t or rather can’t host a 32-bit OS on that without emulating (in a sandbox environment like VirtualBox), then you may see an increase in absolute speed, maybe, just maybe.

    It all goes back to the chip set you have in your system and whether or not you were told the truth about the system you bought; chip set, CPU, memory, etc. Many people are not told the truth about their system before they get it because they wouldn’t buy it otherwise.

    If you do computational work, having RAM with tight timings and descent bandwidth is good but for gaming it’s the opposite, high bandwidth is necessary but go as tight as the RAM will allow at the bandwidth you are running.

    There are far too many variables to accurately say that you will get more computational power out of a 64-bit OS from Microsoft vs. that of a 32-bit OS from Microsoft. It’s all about details, Michael.

    Besides, a video editing piece of software, you should be using workstation grade video cards with a lot of texture RAM among other things and usually those workstations have big beefy CPUs in them, AMD Opterons or Intel Xeons for the big companies that do this for a living. When you do video editing, it’s never done in real time so some people can get by with a 32-bit system, depending on again the details of the project. While, I personally would use a 64-bit system, I also would be using Linux x64 (custom kernel and scheduler not to host the common 32-bit applications and processes (er, I should call them daemons) to do what I need to do. 🙂

  23. Alex 10 years ago

    I have some news for all of you that think that the Apple Macintosh computers based on the Intel series CPUs is a good deal. They really aren’t. They are standard workstation motherboards with Apple Computer’s name silk screened on them.

    Snow Leopard has more things in common with FreeBSD than NextStep from the days of the NeXT computers. The bulk of the source code was back-ported to the newly OpenDarwin standard before it was shutdown and absorbed by Apple Computer as well as the people who worked on the OpenDarwin OS itself. By the way, you can get a copy of FreeBSD and source code if you are brave enough (let alone know what you are doing with a compiler, debugger and linker).

    You can get incomplete open source for Darwin except it doesn’t include the Xfce GUI desktop, for which you have to come up with yourself.

    The same problem is found on Apple based on the Intel series of CPUs and chip set that plagues the standard PCs. You install 4GB of RAM, some of the chip set gets in the way and occupies the RAM space of the 4GB you’ve installed.

    Now if computers were designed correctly, you would have accessory space as a page or separate address space in parallel to the main memory and accessible through special registers in the CPU or MMU (Memory Management Unit, the old days back in the early 1980s to 1990s they were still using these as a separate chip outside that of the CPU itself).

    The problem with this design however is that the accessories would then need their own scratchpad memory aka work RAM which is well, expensive. I know there are computers out there with this exact configuration but most of them are relegated to R&D work, drug and genetic research for the most part. They don’t have the idea of extended memory as I said before, they have expanded memory, direct mapping of components or options in accessory slots and of course a crap load of RAM. Since the memory is accessed as a linear block, there is less programming necessary for this type of addressing mode.

    Granted, these next two companies I can consider a worthy opponents as they do workstation and server motherboards however I am currently in a private industry with clients with special considerations, so I don’t see them as a threat, more of a friendly competition. I will vouch for the quality and services of both SuperMicro and EVGA, they both make great Intel dual Xeon based motherboards for which if you felt adventurous you could actually make a Apple Darwin clone and desktop GUI of what Apple calls OS X, Snow Leopard and Lion releases with these boards.

    However, a notable mention is another group doing just that, making an operating system to work along side OS X except for free, don’t have to pay for it. They are running into some hitches here and there but I am sure they will figure it out, they’re a bright bunch of people. The name of project is called, PureDarwin, just Google or DuckDuckGo it.

  24. Alex 10 years ago

    Also, there is an edition that can go above the 192GB RAM barrier however, the cost of the OS itself from Microsoft is horrendous. The maximum memory it can access is 512GB RAM. Also, the problem with chip sets getting in the way of the full 512GB RAM also occurs even on the 64-bit systems. Even if you have the full 512GB installed, you won’t be able to use 100% of it. 🙂

    Look up the following:

    Microsoft Windows 2003 64-bit Datacenter Edition

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