well one there is no such thing as a 3 ghz motherboard. Motherboards are the conductors of the information. The CPU does that.
2nd. This depends if your talking about a processor that can do 3 ghz. or One that is factory rated. When you figure that out. Pricewatch.com can give you the lowdown on some pricing.
It's limited by your motherboard on what CPU it can take. The list of supported processors is most likely listed in the manual.
Any one, the cheapest will probably do the job though
3GHz is the fastest 1000 Mhz is second fastest
3ghz-300ghz
One of the best is the Intel D865GVHZ ATX Motherboard w/Pentium 4 2.4GHz CPU.
1
The cheapest and easiest way is to upgrade RAM. If money is no object, Upgrade RAM Motherboard and CPU.
The HP Pavilion is the cheapest model currently on the market from HP computers. It has a lower end processor and motherboard but will function fine for general web surfing, checking email and updating social media.
No. The Celeron is much slower.
That particular model is a desktop; you should be able to find any number of inexpensive motherboards that will fit in the case.
3GHZ
Usually Pentium 4, 2/3GHz, 512MB/1GB of RAM, 40GB/80GB Hard Drive, Most of the time SATA instead of IDE hard drive (Depending on the Motherboard). Sometimes Graphics card with VGA and DVI ports.