7900gs failures...call dell or mod?

I'm currently trying to decide between calling dell to get warranty replacement on my 7900gs or if I should buy a gtx or a 7950 for my e1705.

The problem is random blue screens in windows related to hardware during games. Company of Heroes is the best at crashing it. I thought I had the problem solved when I opened it up and cleaned the cake from between the heatpipe fins where the fans are on both sides. There was a noticeable improvement in how long it took to crash now. I never have any problems outside games though. Although it takes longer to crash it now, it still crashes. I'm not talking about 8 hour stretch of gaming though. Just 1 match is enough to crash the system in most cases. I was able to extend the life further by reducing the settings a bit on the game.

To investigate further I tried the fangui program. I ran the fans at high (very annoying listening to it spin up and down over and over) and the system seemed to stay slightly cooler. The system was peaking at 61 celsius. I then read that this program doesn't report gpu temps right. I then tried the ati tool which is known to give the right temperatures. This is where the surprise came in. When I did the artifact scan, the system heated up to a peak temperature of 81 celcius! Strangely though, the system didn't crash even though yellow dots where popping up all over that fuzzy cube, indicating hardware failure at stock speeds(I don't overclock), there where also quick flashes of geometry on the cube too. I left the ati tool on overnight. When I woke up, it was still going, it had evened out at about 79 celcius and there where still yellow dots all over the cube.

So, this leaves me slightly confused with a few options. I have not had the system longer than a year. Thankfully, its not my main system, but I do use it frequently. I can call dell and complain to try and get them to send me a new 7900gs and be content with that. I can also go on ebay and buy a 7900gtx for around 400. I have the money, but I just don't know if it's really what I need. I know there are dual heatpipe versions of the card, but I'm not going to buy the same card I already have, but with better cooling. There is also the 7950 gtx for 100 dollars more, but I am skeptical as to how much of an improvement the 7950 is over the standard gtx. I could also do both and sell the rma card on ebay.

The main confusion comes from the fact that I have really not had any problems with the gs as far as being able to run the games I play. Company of heroes stresses it, but I can get a decent framerate and still have pretty graphics with the gs. A chip that didn't overheat and fail would suit my needs. The gtx has better cooling no matter what because of the dual heatpipe, so I am confident that I will get decent cooling with that part. I would like to know what other people are experiencing with this part as far as their temperatures . Is my card really defective? Should I perform the upgrade mod? Should I find a way to undervolt/underclock my card? Is there a better way to cool the chip with heatsink compound ( I don't want to do the hardware cooling mod that is posted here)?