Problems with my old HD 4870

If i play games too long with my Sapphire Vapor-X HD 4870 then the screen becomes black and a red LED burns. I have 3 LED's on my graphics card.The codes for them are D1601,D1261 and D1260.For me  D1601 burns. There's a little bit of text above those LED's.For D1601 it says Overheat protection,which is odd because my max temperature with my GPU is 50°C. Also if i use my computer for a couple of hours it also displays that error.

Could anyone tell me what the problem is?.

 

 

Must be gpu or memory failure, or the diode is giving you wrong info, 4870/4890s have big idle temps because of clockspeeds (for 2D), and the heat shortens it's life (which can only be fixed by undervolting and underclocking to more realistic 2d clocks and normal operation for 3d rendering.

Put the fan on max and test it like that, especially with your cooler, it should drop 5-10c in idle/load. If it doesn't show error it's clearly an overheating issue.

50°C is too low for load, you must have very low ambient temperatures. Most 4870s idle at 70, mine used to at 60 and with underclock it went down to 50-42

I can't put the fan on max because i put a custom GELID GPU cooler on it (http://www.gelidsolutions.com/products/index.php?lid=1&cid=17&id=52).That is also the reason that it doesn't become too warm