The GPU in my dad's pc is at the end of his lifetime it seems. Graphical glitches everywhere, crashes, ... all that good stuff.
I tried downclocking, reïnstalling the games, different drives,... It no use. So he wants to buy a new one. The techie he is, he read something about the GTX Titan in some magazine and tried to convince me to order that one for him. :')
Some extra info:
current gpu -> hd4870
cpu-> AMD Athlon 7850 dual core @ 2.8Ghz
mem -> 4gb I think.
mobo -> ga-ma770-ds3
400W corsair (CX400W)
games he plays (95% of the time CIV 5, some Anno and Farming Simulator I bought him.)
If he is a dad of all dads... Go with the Titan or 7990. I mean if he just wants something that can go through the ages those things are beasts... The 6990 I just recently acquired for a 100 bucks can handle all the games the 7950 I bought for 300... THAT and as mentioned above the 7990 is reduced to 700 bucks!!!!! this thing is two 7950 chips fused on one card... I mention the AMD cards more cuz I fold when I am not at my computer... Nothing like making 100-200 bucks in bitcoins per month on the side... While the Titan gives you a penny... (Exaggeration but not far from...)
Look at the sort of games his dad plays.. and look at the rest of the spec of the rest of the current machine.
just adding a drop in current gen card above a 7770 would make the machine extremely unballanced with most likely not much actual real world performance gains over the existing card.
Well if he has an old CPU and a low power PSU, there is not many big gaming GPU's to suggest. A 400W PSU might power something like a GT640 or HD6670. The processor might bottleneck the GPU too. So keep those in mind.
If your dad does business, go for an AMD Firepro or NVIDIA Quadro card. Any.
The shop I will most likely be buying the cards from is http://www.power4pc.be (It's in English) It has these prices for some of the cards suggested(cheapest manufacturer):
hd7770 - €96,49
hd7790 - €111,74
hd7850 - €138,55
gtx 650 - €91,16
gtx 650 ti - €114,63
Tbh, I think that anything heavier will be overkill and that the cpu will bottleneck it (tell me if I'm wrong please).