I see what you're saying but what you're saying doesn't make logical sense.
Thuban will be an AMD Istanbul chip with support for DDR-3 memory. Currently a Core i7 (Lynnfield or Bloomfield based so both 1156&1366) easily outperform Istanbul on Multithreaded applications with both CPUs being clocked at near the same speed (2.6GHz vs. 2.67GHz).
So it's nice that you can purchase an AM3 motherboard with a Phenom II X4 955 right now and upgrade to a Thuban when it comes available but you could also purchase an LGA 1156 motherboard with a Core i7 860 and get higher than Thuban performance RIGHT NOW for nearly the same amount of money as an AM3 motherboard and Phenom II X4 955.
So I really don't get your logic... why pay for two CPUs when you can pay for one today which will be faster?
See you're thinking Core i7 860 and thinking $279:
http://www.newegg.com/Product/Product.aspx?Item=N82E16819115214&cm_re=i7_860-_-19-115-214-_-Product
I'm thinking Core i7 860 and thinking $229:
http://www.microcenter.com/single_product_results.phtml?product_id=0317378
And a Phenom II X4 955 (C3 stepping the new one) is $175.99:
http://www.newegg.com/Product/Product.aspx?Item=N82E16819103808&cm_re=Phenom_II_X4_955-_-19-103-808-_-Product
That's not a huge difference... considering that if you want to get Core i7 860 performance you'll NEED a Thuban. That means buying a Thuban when it comes out.. so $175.99 + Thuban's price. Doesn't make sense.
You state that going LGA1156 means you're settling for second best. Going for AMD means you're settling for third best. I don't get your point there either.
Oh I see what you're doing. You're seeing AM3 as being a comparable product to LGA 1366 and LGA 1156 being second best. You claim features are lacking in LGA1156. Like what features exactly?
If you're talking i5 specifically.. it lacks QPi and HyperThreading... do AM3 CPUs now have HyperThreading?
If you're talking LGA1156 having less features than LGA1366 (Dual Channel vs. Tri Channel)... does AM3 have Tri Channel now? And yes we know LGA1156 lacks the QPi bus but from benchmarks comparing LGA1156 to LGA1366... it really doesn't make a difference does it?
The reason why your argument don't make sense is because you're tailoring the specifics and facts (it's called spinning) to suit your world view (AMD4Life!). It doesn't work that way.
AM3 does have some advantages over LGA1156. If for some reason a user wanted to pair two Radeon HD 5970s (not 5870s) in CrossfireX then the PCIe controller on the LGA1156 Processors might not be enough. You could claim that AM3 has two or more x16 PCIe slots available. But then you'd be ignoring the fact that both platforms would be GPU bottlenecked so it really wouldn't make a difference.
AM3 will have support for the initial Bulldozer CPUs. But if we look at AMDs track record with AM2 boards getting AM2+ support or worse AM2 boards getting AM3 support we're left with a sour taste in our mouths. Also many Phenom II X4 AM3 buyers bought cheap motherboards which, as is always nearly the case, likely won't get Bulldozer support added to them or won't be compatible due to VRM/Component issues (we know that nVIDIA Chipset based AM3 boards won't get support for example).
Right now... the only compelling reason to go AMD is if you REALLY can't afford the extra $50. That's it.