One memory overheating in dual channel

I have a gigabyte ga-ma790x-ds4 motherboard running with a geil dual channel 2x2gb kit 800mhz 5-5-5-15 1,8v. I have recently upgraded its bios to the latest version F8 and i mounted a new Athlon II x2 250 3,0 GHz. Right after that the mb detected that the cpu has 2 memory controllers and autodetected unganged mode for the 2 memory modules. the effect was that after a short time the second memory module started overheating very badly, although it had a metal heatsink. the first memory module, though, stayed at room temperature. I immediately changed to ganged mode in bios and that seemed to reduce the second module's temperature but it still stayed roughly at 60 degrees. The system was running fine and no errors were found with memtest.
I have seen this problem before, only much worse, with Asus M2N68 (i tested several). The mb would function fine with one memory module but with 2 modules the second was getting very hot and roughly after 15 min of functioning memory errors would start to appear in memtest. Despite the fact that those motherboards had 4 dimm slots i could never get them to work with more than 1 memory module.
Has anyone seen this before. Any idea what's causing it? My pc runs fine but I am worried about stability.

/ponders

The errors on the old board may have been a chipset issue.

I would give it some cooling, but remember memory can take a fair bit of heat.

maybe something like this would work(that memory is cool the the touch). can cool any area where you find too much heat

Also slot 1 being close to the cpu cooler may get extra air that way as well