The IHS for the RSX on every model between the CECHA/B, to the final slim model 30XX is attached using thermal adhesive/glue on the 4 ram chips. On all super slim models 40XX-43XX the RSX is cooled using direct die cooling with a heatpipe that sits directly on the RSX die with no contact being made to the ram chips.

The 40nm RSX has much stronger glue than that of the 90nm and 65nm, so take care in delidding them if you decide to do so or send it to a professional to be delidded if you so wish. There is no solder on any of the Cell IHS and you can delid them like you would any other Cell, but still take caution and practice on dead boards before you attempt it on a board you care about and potentially make it a paperweight.