Dimension 9150 and Windows 64 bit

Dell only supports (has hardware drivers) for Vista 32 bit.  There are NO Dell 64 bit drivers.  For that reason, I would suggest staying with the 32 bit version of the OS.  There MAY be drivers around for some of the hardware but you probably will not find 64 bit drivers for all the Dell hardware.

You won't really gain much in memory availability with 64 bit and 4GB of RAM as the OS and possibily video will still use a certain amount of the RAM and you will be left with something less than 4GB available.

Thanks for commenting.  I did consider the lack of Dell drivers but found that on installation Windows 7 includes drivers for all the hardware including the Intel chipset.  I have not installed any of the Dell drivers and the machine is up and running fine.  I know I will not gain on memory but having looked around I note that the general advice is to use a 64 bit OS if your system supports it.  My system certainly appears to support it and if the question of drivers is resolved is there anything to worry about? Bear in mind that Dell have not issued drivers specifically for Windows 7 32 bit for the 9150 anyway and I suppose won't guarantee the Vista drivers as compatable.

The Vista drivers should work OK as Windows 7 is basically Vista anyway.  The big issue is the Dell Integrated Audio, we have found that non-Dell drivers either do not work or do not work properly on the Dell integrated audio.  We have many documented cases of that in the Audio section. 

Windows 7 recognised the integrated AC97 audio and installed suitable drivers.  If they prove flakey I could always download others from Realtek.  It appears to be working ok so no problems there.  I am still a little confused about the motherboard capability.  It appears 64 bit capable but in what way is it different from later motherboards?  Is the difference limited to the memory expansion capability?  I note the bios does not allow for the memory mapping feature essential to memory configurations larger than 4Mb but is everything else on the board similar to later boards?  If drivers are available is there a drawback to using this board with a 64 bit OS.  On the other hand what would be the advantage?  I am keen to establish the pros and cons before deciding which version to register with Microsoft.

Windows 7 recognised the integrated AC97 audio and installed suitable drivers.  If they prove flakey I could always download others from Realtek.  It appears to be working ok so no problems there.  I am still a little confused about the motherboard capability.  It appears 64 bit capable but in what way is it different from later motherboards?  Is the difference limited to the memory expansion capability?  I note the bios does not allow for the memory mapping feature essential to memory configurations larger than 4Mb but is everything else on the board similar to later boards?  If drivers are available is there a drawback to using this board with a 64 bit OS.  On the other hand what would be the advantage?  I am keen to establish the pros and cons before deciding which version to register with Microsoft.

You can always re-register it later, as long as you ensure it's only installed on one machine, even if you must phone the service reps.

The drawbacks to using the 64-bit OS are that certain hardware *might* not function correctly. The key word is MIGHT. In many cases, Dell machines are constructed from off-the-shelf parts for which the drivers install automatically. And remember that Microsoft is very, very keen to avoid with Windows 7 one of the biggest flaps they had with Vista: incompatible drivers. I have tested different chipsets and CPUs with Windows 7, and found that it is quite compatible. Even a five-year-old nForce2 board (nVidia did not officially support nForce2 under Vista) worked fine under Windows 7. A six-year-old Dell Dimension 2350 with 2Ghz Celeron worked fine, too.

I tested my Vostro 220S, which does not have official Dell 64-bit drivers, with both Vista and Windows 7 64-bit. It passed my torture test, playing back full-length Blu-ray movies with S/PDIF passthrough, with flying colors.

The worst case scenario would have you reinstalling the OS ... but it is very unlikely.

The motherboard used is a Dell Custom OEM motherboard, not a "standard" or "Retail" motherboard.  Dell tends to do some custom implementation of the Intel chipset, for example, so not all the functions that Intel lists for the chipset may be fully implemented. 

If everything works then stay with the 64 bit.  If there are any hardware issues then use the 32 bit version.  As these models are discountinued (Dell calls them Legacy) your Dimension 9150 and my Dimension E510 will never see any additional Dell drivers.  (Keep in mind Dell is in the business of selling new PC's).

An example of not fully implementing an Intel chipset;  the chipset on my E510's motherboard (made by Foxconn for Dell) according to Intel will accept upt to a D960 dual processor CPU, however the Dell custom implementation will only allow up to a D945 CPU.  There are only Vista 32 bit Drivers for my E510 and although I'm not planning to install Windows 7, but if I did, I would stay with the 32 bit version since there are no Dell 64 bit drivers.