Personally, any ddr2 modules with >2.1v vdimm would really need some form of direct airflow over them regardless.

I always have my memory actively cooled rarely hit over 35-45C even with alot of voltage and looping memtest86+ v1.70

I find 3x 60x25mm sunon 23.5cfm maglev fans strapped together side by side over modules really effective in cooling memory