The Antec VP450P isn't Haswell compatible.
Antec:
According to Antec, the following units are "fully compatible" with Haswell:
EarthWatts Green: EA-650 Green
EarthWatts Platinum: EA-450, EA-550, EA-650
High Current Game: HCG-750, HCG-900
High Current Gamer M: HCG-520M, HCG-620M, HCG-750M, HCG-850M
High Current Pro: HCP-750, HCP-850, HCP-1200
High Current Pro Platinum: HCP-1000 Platinum, HCP-850 Platinum (OC link), HCP-1000 Platinum (OC link), HCP-1300 Platinum (OC link)
NeoEco C: Neo Eco 620C
Signature: SG-650, SG-850
TruePower Gold: TP-550G, TP-650G
TruePower New: TP-550, TP-650, TP-750, TP750 Blue
TruePower Quattro: TPQ-850, TPQ-1000, TPQ-1200, TPQ-1200 OC
VP: VP550P V2, VP650P V2, VP650PM
VP F: VP550 F, VP630 F