www.newegg.ca/.../Product.aspx

Wonder if this would work?

We recently purchased a new XPS 8300 which came with a AMD Radeon HD 6450 1GB DDR3 installed and I'm finding it is having a hard time playing any new games such as SWTOR and I have Diablo 3 on preorder.  Can anyone recommend a different card I could just go out and swap with this one?

I would have thought, that card was ok, however, your Power Supply Unit below,

Power
                                                 (optional)         wireless technology
DC Power Supply

Wattage            460 W                         Physical

Input voltage      115/230 VAC                   Height          407.75 mm (16.05 inches)

Input frequency    50/60 Hz                      Width           185.81 mm (7.31 inches)

Output current     8 A/4 A                       Depth           454.67 mm (17.90 inches)

                                                 Weight          10.18 kg (22.40 lb)

is good enought to run any card. What you will need to do is check your PCIe power cable, because more powerful cards require their own power supply. If you don't have any PCIe power cables, then you will need a new PSU.

Has you can see for this card below, you wil need PCIe power cables,

Suggested AMD Radeon™ HD 6950 System Requirements

• PCI Express® based PC is required with one X16 lane graphics slot available on the motherboard
• 500 Watt or greater power supply with two 75W 6-pin PCI Express® power connectors recommended
• Certified power supplies are recommended. Refer to http://ati.amd.com/certifiedPSU for a list of Certified products
• Minimum 1GB of system memory
• Installation software requires CD-ROM drive, a keyboard, a mouse, and a display
• DVD playback requires DVD drive and a DVD
• Blu-ray™ playback requires Blu-ray drive and a Blu-ray disc
• For an AMD CrossFireX™ system, a second AMD Radeon™ HD 6900 Series graphics card, an AMD CrossFireX™ Ready motherboard and one AMD CrossFireX™ Bridge Interconnect cable is required
• Use of 3 or more displays with AMD Eyefinity technology requires a DisplayPort-capable panel or an AMD Eyefinity validated dongle. See http://www.amd.com/EyefinityDongles for a list of validated DisplayPort dongles.

It will work.

www.newegg.ca/.../Product.aspx Wonder if this would work?

Yes, no problem.