Can I install a 64bit OS on a Dell Optiplex GX260?

If it is a Socket 478 chip then no. If the GX260 has an upgraded board that has a Socket 775 and you have the matching Prescott chip (517 or 524) then you will be able to do 64-bit.

The 3.06 P4 HT is a 32 bit chip, so no, you cannot install a 64 bit operating system

If you were to go for any of the dual or quad core processors, these are all 64-bit, but it'd probably mean upgrading the motherboard yet again.

The thing about 64-bit OS is that he performance benefits only tend to become hugely noticeable, when you already have a fairly powerful machine, AND you're doing a lot of demanding work like video editing, or music recording etc.

For day to day stuff like 90% of people use their computer for, 64-bit is nothing to write home about really. Besides, its still often quite hard to find 64-bit drivers for older hardware. I have a Dell printer where only half the features are working, because even though its a recent printer, Dell didnt bother to write any drivers for 64-bit Windows for it

Dell Optiplex Gx260

I am not 100% sure if the chip is but it is not advisable to run windows 7 ultimate 64 on that PC. The recommendation for 64bit is 4gb memory and you will miss out on all the best graphics for Win7. Your best bet is Windows XP 32 bit. With the components, you should zip right along for a few years. (Don't expect great graphics in any games with that video card and some games will not run with that card anyway).

um quick question why would you want to 64 bit is for newer pc s that have massive amounts of ram this deel isnt new and doesnt have a massive amount of ram old ram at that forget the points if you do this you take a real chance of burning the thing up it will probably hold the 64 but running it on a p4ht that barely makes it to dual core status um the best thing is to try and see but have a 32 bit disc handy in case it goes south is my suggestion

Optiplex Gx260

Download the free Windows 7 Update adviser from microsoft. Get your rig running on an earlier version of windows download the update adviser, and it should tell you what upgrades you will need to make.

first offm ram is added on, not built in. second, if you have one stick and 256MB then its one stick of 256MB, dont pay attention to what they say online. thrird, older dells had something called dual inline memory meaning you could only use quantities of your lowest amount, so if you were to put a 256, 256 and 512 stick in there you would have 768 which better then the 256 you have now. it wont hurt anything to have different sticks do go for it.