Sorry, I can't answer your question, but I have been actively seeking the answer ever since Ivy Bridge motherboards were released. As far as I know, the answer is that there has been no published testing that demonstrates any improvement over the position with Sandy Bridge platform.
When Anandtech tested an Ivy Bridge CPU in an Asus motherboard ("Intel's Ivy Bridge: an HTPC perspective", published 23 April 2012), they found no improvement, but were told by Intel there was a fix "in the latest production BIOS on their motherboard". This presumably means the Intel DH77EB motherboard. The latest production BIOS for that board that has been distributed is dated 26 April. However, I have not found anyone claiming to have tested this motherboard for this issue.
My hope/expectation, based on statements by Intel, is that there may eventually be some improvement via BIOS updates, and that you are likely to need a motherboard with a 7-series chipset (e.g. Z77 or H77). It is unclear if it will matter whether you use a Sandy Bridge or Ivy Bridge CPU in that motherboard. (Remember, you can use an Ivy CPU in a 6-series motherboard, or a Sandy in a 7-series.) Considering that dual-core Ivys have not yet been released, and may not be for several months (excepting the imminent but specialist/expensive i5-3470T), that could be significant. Until then, there is Reclock, a discrete GPU, or just not caring.