Dell 620 MT

[DarkNebula77]

Hello,
I have a dell 620 mt with a quad core i5 (2.9 GHz), 8Gb of ram and a 300w psu. I was looking to upgrade my psu to this

http://www.amazon.co.uk/Corsair-CMPSU-430CX-Builder-Series-Supply/dp/B0045Y1EI4/ref=sr_1_3?ie=UTF8&qid=1349463268&sr=8-3

and my graphics card to this

http://www.amazon.co.uk/Sapphire-Radeon-HD7770-Graphics-GDDR5/dp/B00761YFGQ/ref=sr_1_1?ie=UTF8&qid=1349470743&sr=8-1

or

http://www.amazon.co.uk/Sapphire-Radeon-HD7750-Graphics-GDDR5/dp/B00761YFPW/ref=cm_cr_pr_pb_t

does anyone know if this will work well with my computer (its not the mini tower btw) and would you suggest a different graphics card/psu in the same price range.

Thanks in advance for any advice

p.s its for some casual gaming

 

[DarkNebula77]

I have also looked at this:
http://www.amazon.co.uk/Sapphire-Radeon-HD7750-Graphics-GDDR5/dp/B00761YFPW/ref=cm_cr_pr_pb_t