1000Mbps is showing 100Mbps in ESXi5 & win7

Hi

i got an issue of bandwidth while exporting  OVF template from ESXi5 to my laptop, the speed was very slow. so i checked the  LAN properties details, the  speed was 100Mbps. but every physical component like cat5e cable  which is directly connected to the ESXi supports 1gbps, the laptops' LAN card supports 1gbps & the LAN card of Host Machine also supports 1Gbps.  & when i am unplugging the cable & plugging it back immediately it is showing 1000Mbps then after few seconds its showing 100Mbps. so where is the problem, i m unable to figue it out.

why it is happening i am not understanding?

here are the links:

ESXi Host's LAN card:

http://www.realtek.com.tw/products/productsView.aspx?Langid=1&PFid=5&Level=5&Conn=4&ProdID=12

My Laptop HP DV6-6186nr

http://h10025.www1.hp.com/ewfrf/wc/document?docname=c03003981&cc=my&dlc=en&lc=en&jumpid=reg_r1002_myen_c-001_title_r0001

thanks