|"I will probably be upgrading order to keep it competitive."|
As I said, your cpu is a GREAT cpu for it's time.
I have installed two 6000+ and it's sibling a 6400+ on other people's computers, all were the 125 watt model, the lower power 6000+ wasn't available yet, and I was and still am impressed with the performance of both.
You are probably not going to need to upgrade that, unless, possibly, if you MUST play the very latest high end video games. There were very few cpus like the 6000+ and 6400+ that operate at 3.0ghz and 3.2ghz respectively that perform as well as they did / do. ( 6000 and 6400 are AMD's approximate rating of the cpu's perfomance in mhz in comparison to Intel's original P4 cpu. )
The person who I built one of the 6000+ computers for died, and I acquired her computer from her Dad in June of this year for free, because she owed me a lot of money at the time. The mboard it is installed on was upgraded twice, the first time because I couldn't get the NVidia drivers for the main chipset on the first mboard (Asus) to work properly with an ATI AIW card I got a great deal on (the card was worth more than the mboard), the second time because a local power failure event damaged the PCI-E X16 slot circuits (Epox, the last full size ATX AM2+ model they made before folding) and that same ATI AIW video card. The 6000+ is presently on an Asus M3A78 Pro mboard, with 3gb of 800mhz ram, a Visiontek HD AIW video card, and it's running Vista Home Premium and XP MCE 2005 (both are 32 bit), via a third party boot manager program (BootIt! NG) . The M3A78 Pro mboard is compatible with MANY newer cpus including the 6 core Phenoms, but, so far, the 6000+ performs so well, I see no reason to upgrade to a newer cpu. On the other hand, I don't play recent high end games.
(She could move only two fingers and needed to be able to use a touchpad mouse to watch TV, so that's why her desktop computers had AIW cards - she LOVED Media Center's TV card support. )
The 4gb virtual memory address limit for 32 bit operating systems.
An example of 3gb working better than 4gb in a 32 bit operating system. That was done on the computer I installed the 6400+ on, 3gb of ram, XP Home, Sapphire HD 4850 video card.
See Response 6:
By the way, multiple core cpus are hype.
Most people have few if any programs that can use more than one cpu core.
Server operating systems, high end very expensive scientific or graphics or animation programs, etc. can use more than one, but most people don't have such.
A common exception to that is some recent and fairly recent high end games, but as far as I know, the multiple core support can only be used in Vista and Windows 7 for them, and I haven't heard of any that use can use more than two cores.
So - dual core cpus are fine for most people, at the present time, if you're running Vista or Windows 7, and you want to use something, such as high end games, that can use more than one core.