thermal conductivity

Coollaboratory Liquid Ultra: 38,4(W/(m∙K))
Coollaboratory Liquid Ultra: 32,6(W/(m∙K))
silver oxide based thermal compounds: ~10(W/(m∙K))
silicon based thermal compounds: ~2,8(W/(m∙K))
Sn96.5Ag3.0Cu0.5 solder, melting point 221°C: 85(W/(m∙K))

My tought is to put the chip back to the IHS/or a custom milled copper block by using solder. You can purchase Sn96.5Ag3.0Cu0.5 as solder paste with flux here:
http://circamicro.com/p-919087-smd29...f-5cc-syr.aspx

..and there's the cooking recipe - see page 2:
http://www.peromatic.ch/d/produkteli...01Feb07%29.pdf