Wow! that was quick! Anyway, it seem like your CPU has been confirmed to support the specific feature that the upgrade assistant has specifically identified as lacking. So, if you are certain that the error message only pertains to the PXE feature, then my guess is that Microsoft simply got this one wrong when they developed their upgrade pre-check requirements. Moreover, I have also noticed that others, with older CPUs, are having issues with other features being reported as missing, when they are in fact there. With that said, I can only hope that people like yourself find a way to report this miscalculation to MS and/or hopefully MS is watching this thread right now and will fix their upgrade assistant. Good luck from here and hopefully they will fix this issue sooner than later. Good luck.
FYI, I have the exact same CPU and we both are running Win 8 x64.A Prescott or an Original Core Duo chip won't run a 64 bit OS, I am running the 32 bit Preview, so I know it was made.
Now, that may be a way to bypass the upgrade assistant issue.You'l have to get 8.1 on an ISO from somewhere.
@dirtyvu: Check out this thread where one forum member claims he was able to download the Windows 8.1 upgrade manually and apply it via a standalone installer. If accurate and true, maybe it would get you past that upgrade assistant issue but maybe not; however, it seems worth trying. Good luck. If this doesn't work, we can resume our communication about the other thingy.
Cannot update to Windows 8.1 from Windows 8 :(
I saw this in the comments on the blog page announcing 8.1
Windows 8.1 now available!
I notice PrefetchW doesn't have a '*' in the CPU features list you posted earlier so perhaps it's the same issue?Chris_D October 18, 2013
I'm disappointed that Windows 8.1 increased the CPU requirements from Windows 8. It's mentioned in the fine print of Microsoft's system requirements, but that's not a change anyone would reasonably expect from a point release.
Specifically, I'm running 64-bit Windows 8 very comfortably on a Pentium D 820 CPU. The Windows 8.1 update appears in the Store but won't install because my CPU doesn't meet the new requirements. The specific extension that Pentium D is missing is called PrefetchW. It's an AMD-only extension that all Intel CPUs either ignore or don't support, and in the past Windows has always suppressed that extension for unsupported Intel CPUs. It's not clear why they chose this point release to quietly change that behavior.
If I reinstall the 32-bit version of Windows 8, I will be able to upgrade to Windows 8.1, but that's a major hassle. Boo to Microsoft for making an arbitrary technical change in a supposedly install-in-place release that will confuse likely thousands of users whose hardware can fully support Windows 8.1, if it weren't for Microsoft's sudden impulse to remove a small bit of legacy code and make life difficult. Microsoft isn't exactly boasting a giant user base for the Windows Store, so it's hard to imagine why they'd throw up roadblocks to encouraging 8.1 uptake.
The 'fine print of Microsoft's system requirements' mentioned above seem to be here:
Windows 8 system requirements - Microsoft Windows
My guess is that you're out of luck for 64-bit, but switching to 32-bit should work... It's a pain though because you'll need to pretty much wipe it and reinstall the whole lot from a 32-bit ISO.To install a 64-bit OS on a 64-bit PC, your processor needs to support CMPXCHG16b, PrefetchW, and LAHF/SAHF
Edit: just checked back and the LAHF/SAHF thing may be a problem too.
Hi David Y,
I (personally) thiink the upgrade assistant just got it wrong in many cases for the following reasons:
dirtyvu is getting a warning that ONLY his PXE option is mising and it is not missing.
Many of the other upgraders (winth different older CPUs) are getting a warning that they have PrefetchW, and LAHF/SAHFmissing, and many are not missing either of those options.
So, if all hold true, why didn't dirtyvu get an additional notification that his PrefetchW was also missing because the upgrade assistant is apparently capable of providing multiple missing option notices?
The reason (I believe) is the upgrade (cross-check) database was possibly constructed incorrectly because it obviously isn't doing a real-time CPU option check.
I remember when I first considered upgrade my old P4 630 (same as Ops) to Windows 8 and the overwhelming consensus was that it would not work, so I just did a clean install of Windows 8, and it worked perfectly (just like dirtyvu did).
In summary, the CPU upgrade assistant is not accurately reporting all mising options 100% of the time so IMHO, the only way we'll know for sure is for someone to attempt a clean install to totally bypass the assistant. I wish I still had my old p4 630 rig so I could do that test but I gave it to the Salvation Army a few months ago.
However, if there is an upgrade issue here, I believe it will be somehow tied to the Secure Boot feature but I cannot say technically how and, BTW, your recommendation to switch to a 32 bit install is also a good alternative to consider.
Last edited by my2cents; 19 Oct 2013 at 06:46.
I think the error message about the processor isn't showing enough detail by not mentioning PreFetchW etc.
However looking at the different system requirements for Windows 8 vs 8.1, and at the info from dirtyvu's coreinfo results, it seems there is a definite change in the system requirements between 8 and 8.1, and that the required feature is just not present on the old Prescott.
Windows 8Windows 8.1
- Free Internet TV content varies by geography, some content might require additional fees (Windows 8 Pro Pack and Windows 8 Media Center Pack only)
You can check to see if your PC meets the requirements for Windows 8 by running the Upgrade Assistant.
- Free internet TV content varies by geography, some content might require additional fees (Windows 8.1 Pro Pack and Windows 8.1 Media Center Pack only)
- To install a 64-bit OS on a 64-bit PC, your processor needs to support CMPXCHG16b, PrefetchW, and LAHF/SAHF
- InstantGo works only with computers designed for Connected Standby
If your PC is currently running Windows 7 or Windows 8 you can check to see if it meets the requirements by running the Upgrade Assistant.
hmmm... that would be a shame if I have to install 32-bit windows 8 before I can move on to windows 8.1.
However, when I bought Windows 8 for the system and went to install it, I don't remember it asking me if I wanted to install 32-bit or 64-bit. It just started installing.
And here's another thing... My father's PC originally had a Windows 7 installation. I got the Windows 8 upgrade ISO. What would be the workflow in this case? Would I have to dig up the Windows 7 image (if there even is one)?
But it brings up a question... If this is an AMD-only feature, how do all the other Intel processors pass the check? And why would Microsoft forces a feature that only AMD supports?
What I would do (and it is a lot of hassle I'm afraid) is find a 32-bit machine, or if you don't have one, use something like Virtualbox to run a 32-bit operating system; for instance a 32-bit evaluation version of Windows 8.1 Enterprise. Don't use XP as you won't be able to create an ISO from there. Also I suspect this is a job for a more modern PC than your father's old one.
Then from that, you can use the webpage to download Windows 8 with just a Product Key (using the upgrade key you used to get Windows 8 in the first place). You can even try the trick described here if you want, to see if you can directly download the 8.1 ISO.
How to download the Windows 8.1 ISO
Once you have a 32-bit ISO, you'll need to do a clean install, wiping the operating system partition, so obviously make sure you have everything well backed-up.