TDP doesn't really matter except where you're running the system flat out. Would it be worth a full platform change? Probably not, if you're looking to stay at a high end system running a lot. The reality is that you'd be better off just cutting back on services. Have a UPC, or even a killawatt meter? Just try different configurations, maybe limit total system power (such as undervolt the CPU) with what you've got.
But it's REALLY hard to see what actual power draw looks like from the wall with all the changing factors (workload, hardware, etc). Basically, you choose between measures of system power for mid to high end parts, or measures of power efficiency for smaller and portable parts. You just accept that power draw for high end systems under high utilization... Are high.