Do I HAVE to format?


Jan 28, 2006
New motherboard, graphics card & CPU but old HDD.

So do I have to re-format my old HDD? And if not (i.e. I just have to re-install windows), will WinXP still recognise my old software properly?

I ask because I would like to preserve my dated collection of installed software, including vintage games from the mid-90s (whose CDs are now long gone :( ).

My old PC (assembled in 2005-ish) which has finally kicked the bucket:

AMD Athlon 64 2.2GHz
Nvidia GeForce 7800GT
Biostar Tforce4 Ultra (mobo...useless)
160GB SATA2 HDD (root drive & still functioning)
200GB SATA2 HDD (still functioning)
Windows XP (SP2)

Prospective new build:

Intel i7 3.2 GHz
Radeon HD5870
6GB DDR3-1600 RAM
Foxconn FlamingBlade GTI LGA1366 (mobo)
1.5 TB HDD

If you format your old hard drive, kiss all data goodbye.

You "may" be able to use your old hard drive and all programs and data (Including Windows), "IF" you don't have an issue with the "HAL" (Hardware abstraction layer). It may be possible to to repair the HAL using the Repair Console.
If you can get Windows to start in the new MB, all on-board device drivers are going to need to be loaded again, but a small price to pay to keep your original Windows installation.

It's nice to see all that RAM , but Windows XP will only use 2 of the 6 GB unless you add the "3GB Switch" to your boot.ini file, then it will actually use 3 of the 6 GB. If you run a 64 bit version of Windows, all 6 GB will be utilized.


Jan 28, 2006
Thanks a lot tig, that answers it all. And I didn't know about the 2GB limit...saved me a lot of future heartache there.



Tigsounds is partly right here.

Since you want the old drive to boot the old OS with programs on a new system, all you need is a repair install which was still available with Windows XP. This will update the HAL and all of your programs should continue working. There is a tutorial sticky in the xp forum if you need assistance with a repair install.

I would first back up the drive before the repair install. Especially since you no longer have many of those programs. Afterall, the HD could go boom someday and this way you would be able to recover your programs. Just recover to new hard drive/computer, repair install, and new drivers.

A repair install will adjust the HAL for your new hardware. And it works from the XP cd itself. So it doesn't have to boot first like Vista/7. With these OS's a repair install requires the OS to be running.

I have no idea where the 3 gb switch thing came from. That is not accurate. XP 32 bit has the same 4 gb limit that all 32 bit OS have. And another 700k goes to hardware addressing so you will end up with 3.2 GB or so usable. Not a problem though. It will run fine. Just cant use all 6 GB while running any 32 bit OS.

Choosing similar hardware isn't a bad idea in this scenario either. If you have not yet purchased, you could go with another AMD cpu and NVIDIA chipset. Its not needed, but it wouldn't hurt either. This definitly would increase the chances of it booting as is. But thats more of an issue with vista/7 because XP still has a repair install available from the cd boot menu. This was removed from vista/7.

I suppose I could have elaborated a bit here about the /3GB switch in the boot.ini file.
The best place to learn about it is from the authors themselves, Microsoft.

Falcon is correct on doing a repair before attempting to run the old drive in a new environment. I feel more at home with the repair console and forget that many people dread it.



Oh, your talking the about the application memory switch. That has nothing to do with how much memory windows can access. That's an application level memory switch.

There is no almost reason to bother with that switch unless your using a 32 bit machine with more than 4 GB of RAM which requires functional PAE.
Retail versions of window do not have that functionality.

32 bit windows by default allocates 2 GB per application. Since it only supports 4 GB which equates to about 3.2 GB usable after hardware mapping, this is almost never an issue with home machines. Rarely does any single app need more than 2 GB on a machine that only has 3.2.

However, certain server editons of windows have a memory extension function known as PAE. PAE exists on most retail versions of windows available the last 10 years or so, but MS disabled the memory extension functionality in those editons.

So if your running 8 GB or 16 GB of RAM, then accessing 3 GB per app makes a lot more sense, especially on a sever or workstation. On a home machine, you already have a 1 GB taken up by the OS, antivirus, and other software leaving you with about 2 GB. So its really pointless.


You're right, most people will never use an app that actually needs the switch. When I saw 6GB of ram in his 32 bit system, it made me think he may be into things that may run better with the switch. I should have asked what mem intensive apps were being used, if any.
I use AutoCad to produce maps of electric utility distribution segments that get very large. They must be fit next to one another on a wall to form a huge interconnecting map of an electric system for use by electric system operators. I dreaded the performance of XP Pro and got the X64 version of Windows and it made a huge difference for the better. The 3GB switch helped in Xp Pro, but just wasn't the answer. I guess the bottom line is if a person runs apps that need that kind of mem shouldn't use XP Pro, and just get a 64 bit system.
Thread starter Similar threads Forum Replies Date
N Windows XP 2