Is it impossible to install Windows 8.1 64bit on a socket 939 computer?

[ZippyDan]

I have done some research on this and I think the answer is: yes, it is impossible. But I thought I would just do one last check here with the experts.

It seems Windows 8.1 has some special requirements for CPU instruction sets, and in so doing will not run on some older hardware.

Specifically, I have some Athlon 64 x2, socket 939 computers, running Windows 8 64bit just fine, which will not upgrade to Windows 8.1 64bit. They meet almost all the CPU requirements, except they lack the following instruction set:

CMPXCHG16b

After doing some research at cpu-world.com, it seems there are no Socket 939 CPUs with that instruction set; however, I am not sure if that database is comprehensive or 100% accurate. Assuming the price is reasonable, I'd be willing to swap out the processors to something that support CMPXCHG16b, if it exists. So anyone out there in the real world have 8.1 64bit on a socket 939 CPU?

 

[mikeymikec]

If a processor doesn't support an instruction, I can't see much of a way around that.

Why not use the 32-bit version? Or Win7 instead?

 

[sm625]

Why would you want 64 bit? It is unlikely you'd have more than 4GB of DDR, and the added bloat of the 64 bit OS ensures that you gain no performance by using it.

 

[ZippyDan]

If a processor doesn't support an instruction, I can't see much of a way around that.

Why not use the 32-bit version? Or Win7 instead?

My question could really be restated as this:

is there a socket 939 processor with CMPXCHG16b ?

 

[TerryMathews]

You can bypass the feature check.

http://forums.mydigitallife.info/th...2-check/page12?p=771750&viewfull=1#post771750

Please note if WU updates any of the patched DLLs you will not be able to boot until you repatch them.

 

[Insert_Nickname]

My question could really be restated as this:

is there a socket 939 processor with CMPXCHG16b ?

No, you'll need an F2 revision or newer. Those are AM2 only. I think E6 was the last stepping on S939.

 

[mikeymikec]

@ OP

You'd have to find the specific processor you want to check, run its product code (on the chip's heat spreader) by the Internet and find out whether it supports that instruction. The problem is that there are multiple versions of particular chips, like say the Athlon 64 3000+ IIRC, made with different core designs.

I was going to comment along the lines of what sm625 said as I haven't seen a mainstream s939 board that supports >4GB RAM, which is why I suggested a 32-bit version of Windows (or Win7 64). I've done two Windows installs recently on s939 boards, but I went with Win7 32 in both cases.

I've installed Win81 64 on multiple Athlon 64 X2 AM2 machines without any problems.

 

[VirtualLarry]

I built a PC for a friend, with a S939 X2 4800+, and 4x512MB DDR. So that's 2GB RAM total. I did put Win7 64-bit on there though, just because. Who wants to be limited to only 32-bit apps these days? (I really love Waterfox, well, except for the latest 31.0 version because it introduced some lag.)

 

[Mem]

I have done some research on this and I think the answer is: yes, it is impossible. But I thought I would just do one last check here with the experts.

It seems Windows 8.1 has some special requirements for CPU instruction sets, and in so doing will not run on some older hardware.

Specifically, I have some Athlon 64 x2, socket 939 computers, running Windows 8 64bit just fine, which will not upgrade to Windows 8.1 64bit. They meet almost all the CPU requirements, except they lack the following instruction set:

CMPXCHG16b

After doing some research at cpu-world.com, it seems there are no Socket 939 CPUs with that instruction set; however, I am not sure if that database is comprehensive or 100% accurate. Assuming the price is reasonable, I'd be willing to swap out the processors to something that support CMPXCHG16b, if it exists. So anyone out there in the real world have 8.1 64bit on a socket 939 CPU?

Short answer is I was in the same boat,you only have the option of 32 bit Win8.1.

What I ended up doing is installing Ubuntu 64 bit on my S939 socket CPU (3800+ X2 Athlon).


It's one of my older PCs so not really an issue for me.

 

[mikeymikec]

I built a PC for a friend, with a S939 X2 4800+, and 4x512MB DDR. So that's 2GB RAM total. I did put Win7 64-bit on there though, just because. Who wants to be limited to only 32-bit apps these days? (I really love Waterfox, well, except for the latest 31.0 version because it introduced some lag.)

Who wants to be limited to 4GB RAM in an environment which will very likely require more? It would make a computer (which already doesn't run particularly quickly) run even slower. A computer of that age has probably already proven that it will need more RAM, I don't think there's a single system s939 system I built which hasn't had its RAM at least doubled at some point due to the basic software requirements increasing due to software updates.

The only plausible scenario IMO for running such an old system with a much newer OS is because the needs for the system are pretty basic (and its user isn't that picky about performance), or if there was a single app which is currently being used on that system which is 64-bit only and there's no viable alternative. That second scenario doesn't make much sense though IMO, a 64-bit only app whose performance evidently doesn't matter than much if you want to run it on such an old system...

 

[Conker10k]

Who wants to be limited to 4GB RAM in an environment which will very likely require more? It would make a computer (which already doesn't run particularly quickly) run even slower. A computer of that age has probably already proven that it will need more RAM, I don't think there's a single system s939 system I built which hasn't had its RAM at least doubled at some point due to the basic software requirements increasing due to software updates.

The only plausible scenario IMO for running such an old system with a much newer OS is because the needs for the system are pretty basic (and its user isn't that picky about performance), or if there was a single app which is currently being used on that system which is 64-bit only and there's no viable alternative. That second scenario doesn't make much sense though IMO, a 64-bit only app whose performance evidently doesn't matter than much if you want to run it on such an old system...

This is like digging up the grave again but i would like to add that i have a dual socket 940 motherboard with pci express with 16GB of DDR1. I also have 4GB sticks of DDR1 i could load in and get 32GB of ram total for DDR1. Some reason Microsoft doesn't want to support 64bit on my cpus either - Opteron 285's. I can only run windows 8.0 at this point. Nothing is slow either with this machine. I got a cheap 6000 series amd gpu in it. Works great. OS and everything is smooth and butter like if it was a new machine. Sucks how they stopped supporting these cpus after 8.0. I could understand locking out support at windows 10 but at 8.1 from 8.0. That's just ridiculous. I got more ram than some people here and thats DDR1. I am maxing out a 100mbps internet connection while having over 30 tabs open in firefox. This is no slow machine like some people think because of the age.

 

[VirtualLarry]

Who wants to be limited to 4GB RAM in an environment which will very likely require more? It would make a computer (which already doesn't run particularly quickly) run even slower. A computer of that age has probably already proven that it will need more RAM, I don't think there's a single system s939 system I built which hasn't had its RAM at least doubled at some point due to the basic software requirements increasing due to software updates.

The only plausible scenario IMO for running such an old system with a much newer OS is because the needs for the system are pretty basic (and its user isn't that picky about performance), or if there was a single app which is currently being used on that system which is 64-bit only and there's no viable alternative. That second scenario doesn't make much sense though IMO, a 64-bit only app whose performance evidently doesn't matter than much if you want to run it on such an old system...

I disagree. The extra GPRs of 64-bit mode allow applications to run faster than they would with 32-bit. As long as you have enough RAM for the working-set (aka aren't "thrashing" the pagefile), then I would take 64-bit every time. Even if it does lower the L2 cache hit rate slightly because of the larger memory-management data-structures.

The computer in question, is primary just used for web browsing, and listening to internet radio, and possibly burning a CD.