you mean Pagerank or site ranking? I heard is better to have dedicated ip than shared ip with 300-400 websites. Some says it will help in google serps. When I only can get dedicated ip for website - I do this.
i want to change my server (host will remain same) is it good practice, u can see my sms site goes down 3rd time in 15 days for 15-25 mins
Changing Server will not change the IP if you have a dedicated one. But, if you are on a shared server with shared IP, then it'll change. It'll have no or very little impact on the SERP. So, i'd suggest you to change the servers.
It plays like this: if you change your host ip from america datacenter to europe your rankings might decrease a little for a while if you change from america to america it really doesn't matter my tip: buy a dedicated ip which will point only for your site(s)
because if google see that all your sites are in the same IP range, they might think that you are just spamming using different sites.
I do not think IP is that important. Because many people from different countries are using same blogger or same site IP but they have different ranking results.
I suggest that you put some focus on link building to your DOMAIN... IP doesn't really matter! Just your web address (Aka "Domain name")
I think IP plays a role in PR or SERPs but most importantly, if I am going to have 1mil UV/month, i will change to dedicated for sure. I dont know whether its relevant or not, but I want to give my visitors the best possible performance while they visit..
Changing the IO won't impact ur serp unless u are changing from an IP located in UK to another Located India. In the later case u might see changes in the SERP for google.co.in and google.co.uk, and also from where the visitor is doing the search
I think there is no role in IP... excluding> only if you submit your site to directories which are placed on the same IP (server)