I am buying a laptop and pretty much decide to go with hypersonic fusion EX-7 model. No any experience with hypersonic before. I do read some complaint about the company,but I feel this company is something to try.At least,they are only vendor providing burn-in procedure before ship out,this will prevent some mistakes.Also, you know what kind of RAM you are choosing(Crucial,Corsair etc.).From other vendor,no such thing,you might get very cheap ram,never know.So I want go with them.

But here comes D900K,sounds good.So i am not going to place order for Fusion EX-7 until I can get some information about a Hypersonic D900K laptop

As you can tell from monitoring the Sager web sites, this model will not be out until October it looks like at the earliest. Also, this is assuming that HyperSonic carries this model as well, which I would guess they would.

The only major difference is the AMD CPU obviously. Also, depending on the exact chipset, it appears this model will support a max of 2GB DDR RAM from early reports. The D900T platform can at least utilize ~3GB DDR2 memory.

Other than that, these systems will be mirror images of each other. It pretty much just comes down to preference of AMD vs Intel.

I do agree with you about HyperSonic and memory choices. I paid the extra amount and got all Corsair memory. It is well worth it in my opinion. They don't list this option on the Aviator EX7 model anymore (just Fusion), but I am sure it can be done with a phone order modification.