I'd like to share my experience with a cluster of 5800 and R80.20 that's running almost all usual TP blades.
By default they run Xeon processors with Hyperthreading so you have 8 cores. I ran the cluster on R80.20 Take 47 for some weeks.
Then when Take 87 came out, I upgraded the standby member vie CPUSE, it rebooted and rejoined the cluster.
Unit A: R80.20.47, Unit B: R80.20.87.
Causing a ClusterXL failover from unit A to unit B caused a CPU error which completely crashed the box, nothing responded short of serial connection.
Reimage, then reinstall of Take 87: same issue. Try a week later with Take 91 when it becomes GA, same crashes happen. Works fine with Take 47 though so I was stuck to Take 47 on that cluster of 5800.
I'd go with R80.30 Take 19 which is anyway the recommended version, it works and cluster failovers didn't cause these crashes anymore.