M17xR2 eSATA support SATA/150 or SATA/300?

So I found this article and know that the Alienware M17xR2 comes with an eSATA port, my question is, does it support SATA/150 or SATA/300 external Hard Drives? While were on the topic, where can I purchase external hard drives that support the eSATA/300? Its known as eSATA-300 external hard drives as shown here: http://review.zdnet.com/filter/storage-interface/esata-300?categoryId=3186&filter=502672_17956888 denpending if the port on the m17xr2 supports esata-150 or esata-300. Here is a good example, look at the supported interfaces. See esata-300? http://www.geeks.com/details.asp?invtid=301442U-DT&cat=HDD 3Gbps(eSATA) and 1.5Gbps(eSATA)

http://www.wisegeek.com/what-is-esata.htm

When purchasing an eSATA controller or bus card, be sure it supports the SATA standard required by your SATA hard drive(s). Hardware that supports newer standards is usually backwards compatible with older devices, but the reverse does not hold. An eSATA controller made for SATA/150, for example, will not be able to support the faster transfer speeds of a SATA/300 hard drive.