Will this GPU work in my Alienware X51 R2?

Solution
Nvidia states that a 400w PSU is the minimum for a 1060. 330w will do in some cases that the rest of your system does not draw much power. If it does then you shouldn't go for the 1060 but for the 1050 ti instead.
Most prebuilts have bad PSUs. You should check what yours have by looking inside your case for a make and model and while you are there, the number of Amps in the 12V rail.

I am 99% sure that it will not be a good PSU so I would advise buying another decent PSU for your rig. Any Seasonic PSU would be an excellent choice. Or you can have a look at tier 1 (overkill in your case) and tier 2 (these would be the best for you) from this link:
http://www.tomshardware.co.uk/forum/id-2547993/psu-tier-list.html
 

JWex123

Prominent
Jul 19, 2017
2
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So I looked up my psu (it is an external power brick) and it is 19.5 Volts at 16.5 Amps, or 330 Watts. Would that not work? I originally had a gtx 670 and the sales rep confirmed that the 1060 they found had a lower "tdp". Would that work for me then or was the sales rep just trying to have me buy something?
Thanks.