XCMS is much more memory efficient. Be aware that each core will use a certain amount of memory. So on a system like yours not using all cores will use less memory and might save you if memory is your bottleneck. Also don't use 80 cores on processes that are bottlenecked by HDD reads (like reading the raw data).
That said, with 10,000 samples you really need to be careful about how greedy you need to be in terms of how low in intensity you want to pick.