Radeon R5 230 

Joseph is absolutely right. Some people have cards that IDLE at 125f (~51c). Most modern AMD GPUs can safely be run at 70c (158f) continuously with no long term reduction in life expectancy. Just to be clear, you would't WANT your card to idle at 51c, lower is always better, but that's just to give some perspective. Glad to hear you've moved on from that low-level card though onto brighter horizons :) BTW, you can easily snag an HD 7950/7970/280/280x on ebay for $100-$150 used these days. Not much you won't be able to play w/one of these.

Thanks for your suggestion, Joseph, but I decided to buy a higher-rated graphics adapter, instead of retro-engineering the Radeon. Again, 125F may be acceptably warm, but long-term, the story about its failure rate may be different.

That's 125F, and not C? 125F is perfectly fine for a GPU. You don't really have to be concerned, until it's going past about 155F or so. If you'd still like it to run cooler, though, zip-tie or double stick-tape a small fan onto it.

Just mount a fan on the passsive heatsink? zip ties is your hero ;)

install a new driver

If you play Minecraft or Team Fortress 2, or probably other games, don't get this card. A friend got it for me, and I installed it and updated the drivers for it. It's actually pretty fast, at least with a 6-core main CPU. However, it's still buggy, and causes lots of polygonal errors in Minecraft. With TF2, it plays for a couple seconds, then hangs for a moment and restarts the entire machine. No BSOD, just black screen and then BIOS beep. Portal 2 works well, with only a couple minor texture glitches.

Recently, I was given a Radeon R5 230, with 2gb, so no money was lost. But aside from low-end performance, my main concern about this card is heat. With full case ventilation, I recorded 126F, so the card's passive heat sink is definitely not doing the job. What options do I have to cool this card? It occurred to me there might be an aftermarket cooling fan, but I am not sure how that would work with the passive heat sink. If I remove the sink, even to install a cooling fan improvement, ATI probably will void the warranty. So, the better course is to retain the heat sink and put the fan on top. Ideas?