25% more L3 cache, 12% faster base clock speed, higher TDP means less likelihood of throttling back on TurboBoost under heavy load, quad-channel vs dual channel RAM, support for 256GB of RAM vs 32GB, 40 PCIe 3.0 lanes vs 20, and list continues...
But that all said, TDP has very little to do with actual power consumption. A E5 system will have far higher power consumption than an E3, but that has more to do with the fact that most of those boards come with SAS controllers and other high-power accessories. If you measured the CPU alone there wouldn't be a huge difference between them at idle.
for typical soho, nothing differences in idle consumption
for Home and personal developer machines that mostly idle. this is a consideration
.
this was the reason I pick E3...., yup memory limitation should be considered.
e5 is good when needs big memory such as running many running VMs 24/7
mine:
my e3 is running 4 VMs 24/7, one video surv.. took a bit hit, and there rest 3 VMs are roughly 40%-50 idle/light weight..
total running with IBM1015, 2 Black WDs, 2 SSD, 1 additional 2 port Intel Nic, and all power s*cker fans in SM 2U server case+ additional 40m sunon cooling. the ppwer consumption takes 50W -60W
running 24/7.
when Video Surv VM is not running, 30-36W consumption.
No