Data Center choice not only IP based?

[yahalimu]

Hi, anyone explain this? On our office network we got 2 PC's running same software, same UK google site and on one PC we're position 13 on the next 16.
I've checked, no difference apart from one's logged into google webmaster.
I understand they choose your data center by IP but I cant explain, when we're coming from the same router therefore ip we get 2 different results...?

[tedster]

1. Being logged in means personalized results can kick in - very likely to be the main factor here.

2. Google's load balancing uses many factors to choose the data center that will be queried

3. Geo-located results use more factors than just the datacenter - there are filters that kick in AFTER the "raw" data is supplied.

[BlueSkyIS]

I typically don't get the same results in different browsers or operating systems using the same IP address on the same computer (IE/Firefox on Windows and Firefox/Safari on OSX).

[yahalimu]

Hmmm.. But its same browser and OS too. Must be cos logged into webmaster then.