As part of that Haswell brought FMA support which was a boon to those of us doing a lot of multiplication and addition (made those workloads twice as fast).
It does depend a little on what ratio of additions to multiplies you had. Haswell dropped down to one execution unit capable of floating point addition, so for addition-heavy workloads you basically had to replace half the additions with fma instructions just to keep your old performance from dropping by 2x.
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As part of that Haswell brought FMA support which was a boon to those of us doing a lot of multiplication and addition (made those workloads twice as fast).
It does depend a little on what ratio of additions to multiplies you had. Haswell dropped down to one execution unit capable of floating point addition, so for addition-heavy workloads you basically had to replace half the additions with fma instructions just to keep your old performance from dropping by 2x.