You could always use separate drives, and then use the boot selection, if your motherboard has that, at boot time.

If not, you can always go into the BIOS to chose the boot drive.

Make sure you only have one of the drives installed at a time when installing though to make sure that one installer doesn't screw up the other.

Are you 100% sure you have a PGA 478 CPU, with 64-bit (or EM64T) instruction support ?

The LGA 775 supported both 32-bit and 64-bit OSes (EM64T) whereas the PGA 478 supports 32-bit only. The Prescott core E0 model F (Pentium 4) was the first one to have the x86_64/EM64T instruction sets, whereas AMD made an x86_64 processor in 2003. I don't think the PGA 478 supports the x86_64 processors (if it supports the Prescott processors, it might).

agent_x007 wrote:

Are you 100% sure you have a PGA 478 CPU, with 64-bit (or EM64T) instruction support ?

RK80546PG0881M SL7QB (the one I have) supports EM64T instructions.
RK80546PG0961M SL7Q8 is also believed to support EM64T.

Asrock P4i945GC motherboard with BIOS 1.30 supports EM64T. I have one NIB.

http://www.cpu-world.com/forum/viewtopic.php?t=23333

bjwil1991 wrote:

The LGA 775 supported both 32-bit and 64-bit OSes (EM64T) whereas the PGA 478 supports 32-bit only. The Prescott core E0 model F (Pentium 4) was the first one to have the x86_64/EM64T instruction sets, whereas AMD made an x86_64 processor in 2003. I don't think the PGA 478 supports the x86_64 processors (if it supports the Prescott processors, it might).

The processors I mentioned above are Prescott E0. Some S478 E0 have EM64T, others don't. Most motherboards don't support it. It was disabled in S478 Prescott G0.

I rarely post without doing my research first.

Wasn't the Pentium 4 EM64T implementation slow? Pretty sure that is what I remember from back then.

And to top it off, Prescott is slower than Northwood clock for clock.

That being said, I wonder if any of the ones I have support EM64T. Think I have 2 3.2Ghz 478 CPUs and maybe 1 3.4.

debs3759 wrote:

bjwil1991 wrote:

The LGA 775 supported both 32-bit and 64-bit OSes (EM64T) whereas the PGA 478 supports 32-bit only. The Prescott core E0 model F (Pentium 4) was the first one to have the x86_64/EM64T instruction sets, whereas AMD made an x86_64 processor in 2003. I don't think the PGA 478 supports the x86_64 processors (if it supports the Prescott processors, it might).

The processors I mentioned above are Prescott E0. Some S478 E0 have EM64T, others don't. Most motherboards don't support it. It was disabled in S478 Prescott G0.

I rarely post without doing my research first.

Ah. Good to know.

Oh so you also own one ?
Good job finding it 😀
It doesn't matter how slow 64-bit mode is.
It enables 4GB+ memory, RTX support (if there will be win7 driver), and NVMe support - that is what's important to me at least 😀

So, if you first installed XP 32-bit and then XP 64-bit, won't the 64-bit's boot loader be able to recognize both installations, and allow you to choose them via boot.ini, like any pair of NT5.x OSes?

agent_x007 wrote:

It doesn't matter how slow 64-bit mode is.
It enables 4GB+ memory, RTX support (if there will be win7 driver), and NVMe support - that is what's important to me at least 😀

You have to post pictures of a Socket 478 Pentium 4 doing real-time raytracing once you get the card and the opportunity. That would be hilarious.

I have XP32, XP64, and linux installed on my main PC. However, I'm using the GRUB boot loader that came with the linux install.
All Windows partitions were created with gParted in order to get proper sector alignment. XP32 was installed first, then XP64. I don't remember if XP64 added XP32 to the boot menu. I think maybe it did not.
After that, I installed linux. The boot loader from linux (grub2) detected the 2 Windows installs and put them both on the boot menu along with linux. I then had to use linux to change the default boot option to XP64 (which is what I almost always use).

The setup was complicated by the fact that XP64 supports GPT partitions *after* booting, but cannot boot from them. XP32 doesn't support GPT at all. I wanted to utilize the full capacity of a 4TB drive, so I ended up with a weird setup involving MBR partitions on a 1TB drive and GPT partitions on the 4TB (which XP32 can't access). XP64 boots from an MBR partition on the 1TB but everything else for XP64 is on the 4TB.

dr_st wrote:

So, if you first installed XP 32-bit and then XP 64-bit, won't the 64-bit's boot loader be able to recognize both installations, and allow you to choose them via boot.ini, like any pair of NT5.x OSes?

It's a vague memory but I think my XP64 install superceded XP32. I hope I'm wrong about that though and it would be worth trying.
If it doesn't work automatically, then I suppose it should be fixable, but I don't know what's involved.

As long as both OS's can read the first partition your fine. so NTFS or FAT32
Windows treats the 32 and 64bit OS's as completely different OS's so the standard boot loader will create a 2nd entry. but do install 32 bit first

As a side note you can actually install 2 copies of the same XP in 2 different locations and it'll create a new entry for that as well (useful but messy for recovering files from a corrupt install)

shamino wrote:

It's a vague memory but I think my XP64 install superceded XP32. I hope I'm wrong about that though and it would be worth trying.
If it doesn't work automatically, then I suppose it should be fixable, but I don't know what's involved.

I'd make a copy of XP32's boot.ini, then install XP64, so that even if the latter didn't keep XP32's entry (I think it should) it would be easy to merge both versions of boot.ini.