Running 64-bit Windows on 32-bit CPU: any point?

General Questions
#1

My company is floating the idea of bumping all engineer workstations up to 8GB of RAM (yay!). However, most engineers are on 32-bit Windows XP, which maxes out at 4GB RAM (boo!)

Before I point this out, I want to prepare myself for the inevitable question “can we just install 64-bit Windows on everyone’s 32-bit hardware, and still see performance benefit from 8GB RAM?” I searched quite a bit, but for some reason all the question-and-answer is of some other permutation of os/cpu/app compatibility than the question I’m asking.

Thanks in advance!

#2

No, there’s no point because 64-bit windows will not run on a 32-bit only CPU.

ETA: now, if they actually have a 64-bit platform (Intel Core/Core2, Pentium 4/D with EM64T, or AMD Athlon 64 or Opteron) then yeah, as long as there are 64-bit drivers for everything you can switch over the OS.

#3

Yeah - it’d be a pretty short conversation due to what JZ said - can’t do it.

However, you might consider going along with the idea, just to see what happens - as a social experiment. Especially if the powers-at-be are the type to get an idea in their head, and obstinantly move forward with the idea due to potential performance benefits of 8 GB vs 4 GB of RAM.

#4

Note that “most engineers are on 32 bit Windows XP”, and “32 bit hardware” are not the same statement. You may, in fact, run 32 bit Windows on a 64 bit processor. If that is the case, bumping to a 64 bit operating system would be feasible. Why would you RUN 32 bit XP on a 64 bit machine? Well, possibly because 64 bit XP was kind of a strange offshoot that was never really supported. They may have bought 64 bit machines in anticipation of a move from XP to Vista, which in light of the problems and bad press surrounding it, they decided to hold off on. Presumably, they would currently be considering a bump to 64 bit Win 7.

#5

Can’t be done. The number of bits refers to the size of the registers and buses on the physical chip. If windows trys to stick a 64 bit number in a 32 bit register, its not going to work.

You can go the other way and install 32 bit windows on a 64 bit machine, and the machine will just use half of each register. But obviously that doesn’t solve your problem.

So I’d say your boss would be wasting money to buy more RAM without upgrading the rest of the machines.

#6

Note also that if a motherboard will even SUPPORT > 4 gig of memory, it’s probably a 64 bit processor. Wouldn’t be much point otherwise. If your management is really clueless, and the 8 gigs won’t even fit on the motherboards, it will REALLY be a short experiment.

#7

Microsoft has a program called the Windows 7 Upgrade Advisor that you can run on your current systems to warn of any potential problems with hardware devices. It will also tell you if you can run the 32-bit or 64-bit versions.

#8

Another thing to consider is the software you use. If it’s all 32 bit SW, there’s little to gain by going 64 bit on the OS.

#9

…except for the extra 4-5 GB of memory specifically mentioned in the OP. No individual 32-bit app will be able to use more than 2-4 GB of it, but the system as a whole will. If these really are 64-bit hardware machines currently running 32-bit OSes, going to 64-bit plus doubling the memory should result in a pretty noticeable improvement, even in 32-bit apps; a lot less hard paging (writing memory to/from disk), for one thing.

#10

I’m reluctant to go against the experts here, but over the past few years most new CPUs have been moving to 64 bit architecture. Your old dusty computer might actually be able to run a 64 bit OS.

Try running CPU-Z on your current OS. Under the “instructions” area in the middle of the box you’ll see some jargon. If you see EM64T (if its Intel) or AMD64 (if its AMD) then your processor is 64-bit capable.

#11

I’ll second this. None of the aps I run are actually 64 bit, but moving to a 64 bit OS and upgrading my ram smoothed everything out.

I run a 3d modeling program on one monitor and photoshop on the other. I keep a browser always open, and run Zune software, Steam, and other messaging programs. My system was chugging at 4 gigs or RAM, but just upgrading to 6 gigs and 64 bit OS made a world of difference.

#12

Right. There is precedent for this in PC history. Windows 3 was 16 bit. The 386 (Intel 80386) was the first 32 bit processor in the PC world. Windows 95 was 32 bit - you couldn’t install it on a 286.

#13

I agree. I would not be at all surprised if the machines were 64 bit. The 64 bit version of windows XP had poor driver support and problems running some programs so most people did not use it and instead used the 32 bit version of XP. The 64 bit version of windows does not seem to suffer from these issues.

#14

It turns out that our machines (well, at least mine) does support EM64T, so I can install the 64-bit OS and exploit that 8GB of RAM (if they’ll provide me with both).

Thanks for all the input.

#15

You may want to check the specs on the motherboard as well. There is usually a max usable RAM independent of the OS limitations (if this a standard box from a manufacturer, this will usually be on the specs page for that product).

#16

You can access up to 64GB of RAM (albeit in 4GB chunks due to paged/segmented logical addressing still being 32-bit) on most 32-bit Intel platforms using PAE. The inability of desktop Microsoft operating systems to leverage this effectively doesn’t mean it’s completely pointless from the motherboard point of view. There are also motherboards that accept both 64 and 32-bit CPUs.

#17

Professional, Enterprise & Ultimate Editions of Windows 7 support up to 192 GB of RAM. It’s only the Home versions that are limited to 8 and 16 GB (Home Basic and Home Premium, respectively).

#18

Those limits are for 64-bit, which won’t run on a 32-bit only CPU. 32-bit versions of those operating systems still max out at 4GB (even though there is hardware support, through PAE, to address up to 64GB on a 32-bit CPU)

#19

The post I was responding to, and quoted, claimed that Windows couldn’t access the full 64 GB some motherboards permit. I was just pointing out that that wasn’t true for all versions of Windows. The fact that 32-bit versions of Windows can only access 4 GB of RAM had already been addressed several times, and I didn’t feel the need to make the point yet again, especially since it was irrelavent to the post I was responding to.