ram blocks connected serial? I strongly advise to connect them in parallel. Ram dissipates only very little heat, almost always even simple air cooling is more then enough, so most cases where ram LC is used it's for bling. But connecting such resistive water blocks as for ram ones (very small crosssection, tight flow bends) in series simply is killing overall flow in loop with no practical gains and hurting cooling of other components in loop which actually make up biggest share of performance and which might profit from extra flow for better cooling/better overclocks.