I likely to start a New vBulletin forum want a reliable hosting. If i had to use a shared unlimited hosting , will my bandwidth and Server CPU usage will reach limit and hosting acc gets suspended? How much does the Bandwidth and server CPU usage does it take if there are always 100 to 300 members ?
Server usage will be high for vBulletin forums no matter how optimized you keep them. I recommend a VPS with 1tb bandwidth for you requirements. Have said that, you bandwidth usage may increase or decrease depending on the user activity and skin used in vBulletin.
You won't need that much bandwidth (as I've seen above 1TB) but you'll need a good chunk of the server's CPU for vBulletin, so a VPS is the best way to go in your case so you'll be sure you won't get suspended if using shared hosting. With cloud VPS hosting you can even choose the CPU power of your VPS, so you can start with around 1Ghz and if you need more they can simply upgrade you to more and more until you reach a decent CPU usage and performance... one of the VPS cloud hosting that I know of is vps.net, you should check them out. Good Luck.
100 to 300 active users everyday? every hour? If everyday then 500GB Bandwidth based on my experience is enough. If every hour than you may need more my friend.
Do you mean 300 member concurrent connection and online at the same time? When you hosting forum,BW is not the main concern. What more important is the RAM and CPU.
Bandwidth is calculated in monthly basis and bandwidth usage is calculated based on number of visits/hits to your websites. For forums 5gb bandwidth is enough for 10,000 hits/month prvided your forum is new and member activity will be in average...