Haswell overclocks worse than Ivy - so even if you get a i5 4xxxk it doesn't mean that you can get the same 4,5Ghz out of it as you did with your Ivy based CPU.
But it's a bit of luck involved - some Haswells do nice, others need insane vcore to get past 4,2 Ghz (and you maybe need to replace the thermal compound between the DIE and the Heatspreader to get good temperature - but this will void warranty)
But it's a bit of luck involved - some Haswells do nice, others need insane vcore to get past 4,2 Ghz (and you maybe need to replace the thermal compound between the DIE and the Heatspreader to get good temperature - but this will void warranty)