Hi, I'm looking to buy a 660ti graphics card. But not sure it will fit in my pc. My mother board is a H81M-P33 and I have 500w power supply and my mini tower is called Cooler Master Elite 342. If you know something please reply. Thanks.
Your 500W power supply could be an issue. You need to verify that the PCIe power plugs on your power supply match the supplemental power plugs on the card you are purchasing. I think most 660ti cards have two 6-pin supplemental power plugs.
The 660ti is compatible with your motherboard and a 500W PSU is enough for it.
The dimensions for the CM Elite 342 are: 180 x 352 x 440 mm / 7.1 x 13.9 x 17.3 inch
Post a link to the GTX 660ti you are planning to buy so its dimensions can be compared to the case. (will likely fit)
If you are looking for a different cheap well performing card I recommend a GTX 750ti or a 1050ti. You can get very small models to fit all sorts of cases and they perform pretty well for most games depending on the rest of your spec.