|"Motherboard: Intel Corporation D945GCZ"|
Your mboard has a PCI-E X16 slot.
The best type of video card in your case is a PCI-E X16 video card - they're the most common these days and likely to be cheaper.
Diablo III System Requirements
Minimum System Requirements
Windows® XP/Vista/7 (latest service packs) with DX 9.0c
1 GB RAM (XP), 1.5 GB (Vista/7)
Intel Pentium® D 2.8 GHz or AMD Athlon™ 64 X2 4400+
NVIDIA® GeForce® 7800 GT or ATI Radeon™ X1950 Pro or better
Your " current video card is: NVIDIA GeForce 6600.." DOES NOT meet the minimum requirements. If it works with the game at all, it will work poorly when the game is set to default settings.
You could try the game before you buy any video card. You MAY be able to tweak settings in it and get reasonable video with a lower resolution setting, etc., in the game itself.
Recommended System Requirements
Windows® Vista/7 (latest service packs)
Intel® Core 2 Duo 2.4 GHz or AMD Athlon™ 64 X2 5600+ 2.8 GHz
2 GB RAM
NVIDIA® GeForce® 260 or ATI Radeon™ HD 4870 or better
If you're in the US
Go to a web site such as newegg,com or tigerdirect.com,
or if you're in Canada go to a web site such as newegg.ca, or tigerdirect.ca, or memoryexpress.com or ncix.com if you're in the west,
or to the web site of a place in your own area (the address is probably in the ads in the Yellow pages for local places that sell computer parts, or search the web for places that sell computer parts in your area and find out their addresses),
search for video cards, then PCI-E ones (you don't want a PCI-E X1 card or a PCI card), and you'll probably be able to select something at the top of the list to sort the list according to Price, lowest first.
Scroll down the list and determine what you can buy for what you're willing to spend. Keep in mind that there will be a shipping fee added on in most cases when you order it from the web.and sales tax added on if that applies.
If you want to see what the total cost is for something on the web, click on Buy or similar, provide enough information for it to determine the final price - you can back out of committing to buy by deleting the item or by changing the quantity of it to zero or similar.
NOTE that some makers such as Asus and MSI currently have Mail- in Rebates available for SOME of their video card models if you buy it BEFORE or ON April 30.
If so, the Rebate will be mentioned in the ad, and usually there is a link somewhere on the web site that tells you the details of what you need to do to get the specific rebate NOTE that if that requires you cut out the UPC code from the box the card ships in and send it with the rebate form, make sure the card works BEFORE you do that - you can't return the card with that missing or cut out and taped on , unless it becomes defective after having worked during the warranty period, which isn't likely. .
You can go here and determine which video chipset provides the better performance for the money you're willing to pay for the video card .
Video Card Benchmarks
NOTE that your power supply's rated capacity may limit which video chipset you can use on a video card you buy.
Your power supply must have at least the minimum capacity required to support a system with the graphics card you are using installed, or the max graphics card you might install in the future.
(Onboard video - video built into the mboard - IS NOT A CARD ! )
If that info is not in the ad for the video card, you can go to the video card maker's web site and look up the specs for the model - often under system requirements - the minimum PS wattage, and, more important, the minimum amperage the PS must supply at 12v is stated. If you don't find that, any card with the same video chipset including any letters after the model number has very similar minimum PS requirements. Some power supplies have two or more +12v ratings - in that case, add those ratings to determine the total +12v current capacity.
This isn't as important over a short period of time....
If you're a gamer...
In most if not all cases, the max capacity rating of the PS is an intermittent rating. It's recommended that you do not load your PS to any more that 80% of that rating if you are going to be using something that puts a constant load on it, such as playing a recent game for hours on end. In that case, you multiply the min capacity stated for the system with the particular video chipset on the card by 1.25 to find the min. capacity of the PS you should have.