I just tried BIOS 1.8 on my MSI H55M-E33 and the power consumption is whack on my i3 530. It idles a full 10-11 watts higher with BIOS 1.8 looking at my Kill-A-Watt. Even the CPU is hotter during idle about 5 degrees Celsius. This is with optimized BIOS defaults with just a few tweaks, so there is something broken in this BIOS.
I noticed BIOS 1.7 had higher power consumption of around 4 watts so didn't use that one either. The CPU temp didn't seem to climb though with 1.7 where 1.8 did.
BIOS 1.5 is very close in power consumption to BIOS 1.3, with BIOS 1.5 maybe about a ~1 watt higher (real close though could be .5 watt). So far BIOS 1.3 is giving me the best power consumption during idle use.
If anyone else can confirm my findings I'd be interested to hear.
Edit: BTW be EXTREMELY careful flashing the BIOS and make sure you know what your doing or you can brick your board. I'm not responsible if your board becomes an expensive paper weight if it fails.