32-64 bit upgrade ~ Questions


D

Dave

hi folks,

i'm currently running a Pentium-4 box with XP pro, and I'm looking at
upgrading my MOBO, ram etc to a 64-bit system.

some elementary questions: what does 64-bit apply to? I've been
recommended Intel i5 & i7 processors, on an asus board, is it the actual
MOBO that is 64-bit (and other hardware like RAM), or is it OS (win7) and
software that is 64-bit? I understand the 'bit' concept in terms of data
"pipelines" but I dont' know what exactly it applies to ... the architecture
of WHAT?

#2: if I upgrade my box to 64 bit MOBO / Win7 ... can I keep my same hard
drives, and perhaps install a dual-boot for WIN7 & WIN XP? I have a lot of
apps & data under XP and I can't afford to lose it. Does Win7 work in the
NTFS filesystem, which I use for XP? AND, in the other direction, will XP
run ok on this new 64 bit board (i5 or i7) ...?

thanks for adding any clarity ...

Dave
 
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P

Paul

Dave said:
hi folks,

i'm currently running a Pentium-4 box with XP pro, and I'm looking at
upgrading my MOBO, ram etc to a 64-bit system.

some elementary questions: what does 64-bit apply to? I've been
recommended Intel i5 & i7 processors, on an asus board, is it the actual
MOBO that is 64-bit (and other hardware like RAM), or is it OS (win7) and
software that is 64-bit? I understand the 'bit' concept in terms of data
"pipelines" but I dont' know what exactly it applies to ... the architecture
of WHAT?

#2: if I upgrade my box to 64 bit MOBO / Win7 ... can I keep my same hard
drives, and perhaps install a dual-boot for WIN7 & WIN XP? I have a lot of
apps & data under XP and I can't afford to lose it. Does Win7 work in the
NTFS filesystem, which I use for XP? AND, in the other direction, will XP
run ok on this new 64 bit board (i5 or i7) ...?

thanks for adding any clarity ...

Dave

It's instruction width.

Instructions are executed inside the processor, so it is a processor property.
It might be referred to variously, as AMD64, EM64T, X86-64 and so on. An endless
stream of techy terms. Check the Intel or AMD sites, to get this information.

http://ark.intel.com/Product.aspx?id=35605&processor=E8600&spec-codes=SLB9L

Instruction set 64-bit

http://products.amd.com/en-us/DesktopCPUDetail.aspx?id=716

Operating Mode 32 Bit Yes
Operating Mode 64 Bit Yes

And in "Table 1. Processor operating modes" here, you can see that a
64 bit capable processor, has several operating modes. "Legacy Mode", allows
a 32 bit OS to be installed. "Long Mode" is for a 64 bit OS, and the
"Compatible mode" implies better backward compatibility.

http://www.codeproject.com/KB/system/AMD64_EM64T_architectur.aspx

As I understand it, 32 bit applications use WOW64 for compatibility on
a 64 bit Windows. But exactly how hard WOW64 has to work isn't clear.

http://en.wikipedia.org/wiki/WoW64

I've run into at least one case in Linux, where you can set up a
"pure" 64 bit mode, implying they're using Long Mode/64-Bit mode.
On that particular OS, if you download some 32 bit code (like
Adobe Flash was limited to at one time), it wouldn't run. So it is
possible to set up things in a very exclusionary way, if you want.
But for the time being, there is still compatibility, as it doesn't
make sense to toss away all those 32 bit applications on a whim.
And that means 64 bit OSes will continue to offer to run 32 bit
applications for you (Windows or Linux).

*******

You need a motherboard that can take your new processor. As long as the
processor is in the "supported" list, that's what counts.

If you go to the motherboard manufacturer site, look under "Downloads", and
check the OS menu there, you're likely to see at least WinXP listed. There
is no reason to remove it quite yet. (Win2K is another matter.)
A motherboard manufacturer sells more motherboards, if they support
a few more OS possibilities.

*******

Windows 7 offers "WinXP Mode", which is a copy of WinXP running within
a virtual machine, relying on Terminal Services to pop up a window and
display the results on the Windows 7 desktop. That is different than
just running an application in some "compatibility" mode, because
the application would be fooled into thinking it's in a real WinXP
environment. The only thing that wouldn't work there, is say
a program that diddles hardware directly - a virtual machine
environment can be poor for things like that (because hardware
can be emulated and not real). Virtual machines are great for
applications that "just like to compute".

"WinXP Mode" is only offered on certain versions of Windows 7,
It's so Microsoft can double their income. This is mainly for
people like me, who buy a laptop, get a lowly version of Windows 7,
which would force me to buy an "Any Time Upgrade", to upgrade my
OS so WinXP Mode would work. So for people who buy pre-built computers
(Dell/HP etc), chances are you'd be paying an extra fee to get
WinXP Mode running. But it wouldn't be much work to do it, just money.

http://en.wikipedia.org/wiki/Windows_xp_mode#Windows_XP_Mode

"Applications running in Windows XP mode do not have compatibility issues,
as they are actually running inside a Windows XP virtual machine and
redirected using RDP to the Windows 7 host. For 64-bit editions of Windows 7,
XP Mode may be used to run 16-bit applications; it includes NTVDM.

Windows XP Mode is available free of charge to users of Windows 7 Professional,
Enterprise, and Ultimate. Users of other editions of Windows 7 are
not eligible to download and use it. This restriction does not
apply to Windows Virtual PC itself."

HTH,
Paul
 
D

Dave

[snip]

thanks Paul, for a very well thought out reply.
I can 'grok' some of it, but i'm not very techy by nature.

it seems quite daunting, actually.

but good to know that some MOBO/chipset combo's will support XP ...

dave
 
T

Tim Slattery

Dave said:
hi folks,

i'm currently running a Pentium-4 box with XP pro, and I'm looking at
upgrading my MOBO, ram etc to a 64-bit system.

some elementary questions: what does 64-bit apply to? I've been
recommended Intel i5 & i7 processors, on an asus board, is it the actual
MOBO that is 64-bit (and other hardware like RAM), or is it OS (win7) and
software that is 64-bit? I understand the 'bit' concept in terms of data
"pipelines" but I dont' know what exactly it applies to ... the architecture
of WHAT?

It starts with the hardware. registers in the CPU are 64-bits wide,
instead of 32. The data path from the CPU to RAM and everything else
is 64-bits wide. So the CPU and the supporting motherboard must be
64-bit.

Once you have 64-bit hardware, you can run 64-bit software on it.
64-bit software can take advantage of the wider words to access more
RAM (just because a 32-bit word can only count up to 4,294,967,296,
but a 64-bit word can count many, many times that.)
#2: if I upgrade my box to 64 bit MOBO / Win7 ... can I keep my same hard
drives, and perhaps install a dual-boot for WIN7 & WIN XP? I have a lot of
apps & data under XP and I can't afford to lose it.

Yes, that should work. You'll have to re-install most apps again on
the 64-bit system.
Does Win7 work in the NTFS filesystem, which I use for XP?

Yes, it can handle NTFS just like the 32-bit version.
AND, in the other direction, will XP run ok on this new 64 bit board
(i5 or i7) ...?

Yes, the hardware will be able to run in either 32- or 54-bit mode.
Until recently a *lot* of 64-bit was sold with a 32-bit OS
preinstalled. Also, your 32-bit software will work fine on the 64-bit
OS, just like 16-bit software works in the 32-bit OS. (But to run
16-bit software on the 64-bit OS you'll need DOSBox or something.)
 
D

Dave

[snip]

thanks Paul, for a very well thought out reply.
I can 'grok' some of it, but i'm not very techy by nature.

it seems quite daunting, actually.

but good to know that some MOBO/chipset combo's will support XP ...

dave
 
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Y

Yousuf Khan

hi folks,

i'm currently running a Pentium-4 box with XP pro, and I'm looking at
upgrading my MOBO, ram etc to a 64-bit system.

some elementary questions: what does 64-bit apply to? I've been
recommended Intel i5& i7 processors, on an asus board, is it the actual
MOBO that is 64-bit (and other hardware like RAM), or is it OS (win7) and
software that is 64-bit? I understand the 'bit' concept in terms of data
"pipelines" but I dont' know what exactly it applies to ... the architecture
of WHAT?

The bits mainly refers to the size of maximum memory addressable. A
32-bit system has 2^32 bytes addressable, which comes out to
4,294,967,296 bytes, or 4 Gigabytes. A 64-bit processor can address upto
2^64 bytes, which is 18,446,744,073,709,551,616 bytes, or 17,179,869,184
Gigabytes, or 16 Petabytes. Basically a 64-bit processor can address
over 4 billion times more memory than a 32-bit one!

That's the simplified version, there are ways of getting a 32-bit system
to address more than 4 Gigabytes. Meanwhile most 64-bit processors
haven't implemented the full 64-bit memory address space on current
generation processors and so they haven't got full 64-bit addressability
yet (not really needed yet).

In practical terms, for Windows users, due to internal requirements a
32-bit Windows was actually limited to less than 4 Gigabytes, somewhere
around 3.25 Gigabytes. So if you had 4 Gigabytes of RAM, you really
needed to have a 64-bit Windows to use all of it. Of course, if you have
more RAM, you definitely needed to use 64-bit Windows no matter what.
Here's a quoted link:

"On system fitted with 4GB or RAM and a modest graphics card with 512MB
of on-board memory the end user normally sees about 3GB of installed
system RAM. So what this means is that the realistic upper RAM limit for
a 32-bit OS is more like 3GB. If you’re adding big graphics cards with
larger amounts of RAM (or using Crossfire or SLI) then you’ll need to be
seriously thinking about a 64-bit OS much sooner."
http://www.zdnet.com/blog/hardware/clearing-up-the-3264-bit-memory-limit-confusion/3124

Now, different editions of Windows 7 64-bit have different memory limits
themselves: the Home Starter and Home Basic, are limited to 8 GB; the
Home Premium is limited to 16 GB; and everything above it, from
Professional to Ultimate are limited to 192 GB. These are just licensing
restrictions rather than physical restrictions. Here's a link:

http://www.zdnet.com/blog/hardware/max-memory-limits-for-64-bit-windows-7/4254

#2: if I upgrade my box to 64 bit MOBO / Win7 ... can I keep my same hard
drives, and perhaps install a dual-boot for WIN7& WIN XP? I have a lot of
apps& data under XP and I can't afford to lose it. Does Win7 work in the
NTFS filesystem, which I use for XP? AND, in the other direction, will XP
run ok on this new 64 bit board (i5 or i7) ...?

thanks for adding any clarity ...

Yes, a 64-bit processor is fully downward-compatible with 32-bit
Windows, including XP, Vista, and 7.

If you don't want to lose your programs from XP. There is a 3rd party
utility that can transfer all of your XP programs and your entire XP
environment to work in a virtualized environment under Windows 7, called
Zinstall XP7. It's a bit pricey, but it eliminates all hassles of
migrating your XP apps, and eliminates the need for dual-booting. I've
used it successfully, and used it to ween myself off of XP slowly at my
own pace.

Zinstall XP7 — Zinstall
http://www.zinstall.com/products/zinstall-xp7

Yousuf Khan
 
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