I kind of expected that reply as I know what the issues are, I was hoping there would be info on a newer forge version that was made to combat the fr issues, its pointless to try build huge builds (like the ones needed to complete AS 1.6.4, as in 1.7 the lag/fr becomes unusable, & from what I hear 1.8 may well be even worse, but there after become easier to mod for, this is just hear say on my part as I have no code skill just google.
1.8 may kill modders, from what I have heard, however I believe it is more stable than 1.7 fr wise. However 1.7 is getting better, and we (as a modding community) will probably be staying with 1.7 for a while, we don't want to rush into 1.8, sorta like we did with 1.7, only to find everything is laggy and broken.
I am not speaking for anyone other than myself here, but I feel like there won't be an "unstable" 1.8 mod pack until July at the earliest. Seeing as there none of the "big" mods (Buildcraft, thaumcraft, tinkers, etc.) released for 1.8, and I always see the release of big mods on the new MC version as a start time before mod packs become stable. Big mods find bugs in the code faster than those that add zombie flesh smelting, and stuff, just because there is a lot more code than can, and most likely will, be broken. Once the first "stable" version of the big mods are out, then I'd say 2 months before enough of the big mods have updated to make an unstable pack, and another few month until players have given enough crashlogs, error reports, etc. before it is possible to see stable mod packs.
I mean look now, it was around the end of the 3rd quarter/start of 4th quarter last year when FTB Unstable was released, and that was damn near unplayable for most people, mod (pack) stability has increased a MASSIVE amount since then, but there is still work to be done