If you don't mind me asking, what setup do you use for temperature control? I haven't really looked into anything more than liquid (looked up submersion a few times, but never tried it).
I started out using dry ice. There are various containers which you can buy for either graphics cards or processors which hold whatever your frozen medium is. In the case of dry ice, you add acetone (or 90%+ isopropyl alcohol to aid the transfer of heat energy). I just recently purchased a 150L liquid nitrogen dewar though, because in the world of sub-zero cooling, colder is better. In some rare cases, people use liquid helium, but that presents a few more issues than controlling condensation.
Dry ice runs ~$1/lb and is at ~-80*C.
Liquid Nitrogen runs ~$1.50/L and is at -196*C
Liquid Helium runs anywhere from hundreds to thousands for a single session, but it's the coldest liquid used at -269*C (4*C from absolute zero).