x64, Explained.

By anthony
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anthony

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On and off, there is an influx of posts related to, or asking, about pretty general or simple x64 related questions. I figured I'd take the time to outline these, and post them for everyone.

Edit 7/22/09

This article was originally written upon release of Windows XP x64. When it was originally written there were only two 64bit processors available at the time, the Athlon64 series, and Pentium 4 processors with a technology called EM64T. The market was really confused by 64-bit at the time, so this was a standard article in terms of explanation, now however things are very different so I'll go about explaining everything differently.

First, Windows Vista and 7 x64 are going to be the standard in the future, and the reason is because as RAM totals grow only Windows 64 can address more than 4GB of ram. Now, technically, Windows x32 can only actually address about 3.2gb of RAM but lets ignore that. Anyways, for consumers, the important thing is in the future, you want Windows Vista or 7 64 installed. Infact, don't even think about it when customizing a computer anymore, its 64 or bust.

When this original article was written most computers had 256mb of RAM, with gaming computers having 512 or rarely 1GB of RAM. My argument at the time was that for enthusiasts with compatible hardware, Windows XP 64 was pretty good. However, don't listen to that anymore, Windows XP x64 in retrospect was a sorry attempt by Microsoft at its first 64 bit consumer OS. Always choose Vista or 7, even if you could miraculously find XP 64.

Either way, I just wanted to update this with information that's slightly more useful. As always feel free to PM me questions, and enjoy!

The original post from way back when

What is 64 bit?

In computer science, 64-bit is an adjective used to describe integers, memory addresses or other data units that are at most 64 bits (8 octets) wide, or to describe CPU and ALU architectures based on registers, address buses, or data buses of that size.

As of 2004, 64-bit CPUs are common in servers, and have recently been introduced to the (previously 32-bit) mainstream personal computer arena in the form of the AMD64, EM64T, and PowerPC 970 (or "G5") processor architectures.

Though a CPU may be 64-bit internally, its external data bus or address bus may have a different size, either larger or smaller, and the term is often used to describe the size of these buses as well. For instance, many current machines with 32-bit processors use 64-bit buses, and may occasionally be referred to as "64-bit" for this reason. The term may also refer to the size of an instruction in the computer's instruction set or to any other item of data. Without further qualification, however, a computer architecture described as "64-bit" generally has integer registers that are 64 bits wide and thus directly supports dealing both internally and externally with 64-bit "chunks" of data.

Source: WikiPedia

What's the difference between x64 and Itanium?

Before the Athlon 64 series, and Intel EM64T, Intel released a server processor called Itanium, and Itanium 2. Itanium is a "true" 64 bit RISC processor. The Itanium (IA64) is considerably different from the x86 variant (x64), and cannot be used with any version of Windows except a specific server edition (Windows XP for IA64 was scrapped).

What Operating Systems can I use with my x64-compatable processor (Athlon 64, EM64T)?

You can use generally any 32bit OS, such as Windows 2000 or Windows XP, or you can use the newer Windows XP Professional x64 Edition. In other words any consumer Operating System will work with your processor.

Is "Insert Program Name Here" slower in an x64 or 32bit OS?

Windows XP x64 uses a compatability layer called WOW64, to emulate a 32bit Operating System. Emulate may paint a picture of VMWare, but it's no slower than running the program in it's native operating system. It will run at normal speeds in x64. Now to reverse that question, a 64bit program, written or compiled for x64, will run or can run considerably faster in Windows x64.

Should I update to Windows x64?!!11!!

While opinions are quite contrary on the topic, I like to believe yes, you should. Assuming you have at minimum 512mb of RAM, and your hardware is recognized (Windows x64 has default 15,000 drivers, more than any other previous version) you'll not be sorry updating now, and not later.

NEW: Should I buy a 64bit processor?

Absolutely. A common misconception as I stated above is that 32bit Operating Systems are not capable of running under Athlon64 or Intel 6xx series processors. Instead, it's the opposite, a new 64 processor, the AMD 64 or Intel 6xx line, of processors are signifacantly faster then older counterparts. The Athlon XP series of processors is now dead, and the Intel 5xx series of processors run extremely hot, whereas their newer counterparts feature "Execute Disable Bit" and sport 2mb of L2 cache.

NEW: Do I need new hardware, or a new motherboard that supports 64?

Assuming of course your processor is supported by that motherboard then no, it should be fine, drivers withstanding, from running the operating system. If your asking do you need a x64 capable Harddrive and ram, well then no, it's generally as simple as the processor understanding 64bit instructions, nothing more.

NEW! From Microsoft!

16-bit applications

Windows XP Professional x64 Edition and x64-based versions of Windows Server 2003 operating systems do not support most 16-bit applications.

Most 32-bit applications that use 16-bit Microsoft ACME Setup versions 2.6, 3.0, 3.01, and 3.1 and InstallShield versions 5.x install correctly.

32-bit applications that are installed by other 16-bit setup programs are not supported. If you try to install one of these applications (other than the supported installers mentioned in the previous paragraph), the message "\Setup.exe is not a valid Win32 application" appears, a message is logged in the system event log, and the Setup program closes without installing or starting the application. If this occurs, contact the application vendor to obtain a software update that is compatible with x64-based versions of Windows Server 2003 operating systems and Windows XP Professional x64 Edition.

For more information about this issue, see the Microsoft Knowledge Base.

32-bit device drivers

Windows XP Professional x64 Edition and x64-based versions of Windows Server 2003 operating systems do not support 32-bit device drivers. Applications that depend on 32-bit device drivers will not function correctly and might cause an error during an installation or operation. Most 32-bit antivirus programs are affected and should not be installed on computers that are running these operating systems.

If an application attempts to install a 32-bit driver, the installation will fail, and the application will have the opportunity to handle the error. If an application registers a driver for automatic startup, meaning the driver should be installed when the system starts, the operating system will determine that the driver is an unsupported 32-bit driver, not install it, and continue installing the other drivers. The event log will record details of the failure, including the name of the unsupported driver and its location. If this occurs, contact the driver vendor for a software update that is compatible with Windows XP Professional x64 Edition and the x64-based versions of Windows Server 2003 operating systems.

If Windows does not start after you attempt to install a 32-bit driver, start the computer using the last-known good configuration.

To start the computer using the last-known good configuration

1. Restart the computer.

2. When the message "Please select the operating system to start" appears press F8.

3.Press an arrow key to highlight Last Known Good Configuration, and then press ENTER.

4.Press an arrow key to highlight an operating system, press ENTER, and follow the instructions.

Note:

This procedure gives you a way to recover from problems such as adding a new driver that is incorrect for your hardware. It does not, however, solve problems caused by drivers or files that are corrupted or missing. When you start the computer using the last-known good configuration, only the information in the registry key HKLM\System\CurrentControlSet is restored. Any changes that you have made in other registry keys remain.

For more information see the Microsoft Knowledge Base.

Microsoft .NET Framework version 1.1

The Microsoft .NET Framework is included in all 32-bit versions of the Windows Server 2003 operating systems. It is not included in x64-based versions of Windows Server 2003 operating systems or Windows XP Professional x64 Edition.

The 32-bit version of .NET Framework 1.1 is supported by 64-bit versions of Windows Server 2003 operating systems and can be installed for 32-bit applications running on 64-bit versions of Windows operating systems (WOW64).

Where can I get more information?

You can of course, post your topic in this forum. Or try Microsoft.

Or, if worse comes to worse, PM me, I'll help :)

Edited by anthony
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Grand Master

dragon2611

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Are 64-bit processors faster with 32 bit software?

586007232[/snapback]

well i certianly belive so my althon 64 3500+ is noticbly faster than my overclocked 2500+ was (it was clocked at 3200+ = 2.2ghz) my a64 is also clocked at 2.2ghz although im not overclocking the a64

id even say its faster than my p4 3.2ghz laptop (mind you its a 533fsb p4 and not one of the 800fsb ones) :yes:

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SkinAddict

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That's correct OPaul, if you run Windows XP Pro or Home (32bit of course), you can use your 32bit drivers for all of your hardware... but if you upgrade to Windows XP x64 Edition, you must have all 64bit Drivers... and as previously stated, x64 has over 15,000 drivers installed by default, more than any previous Windows OS... I've only had one problem, that was my Intel webcam that's about 6 years old :-p.

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