Comparing the 800MHz FSB on Springdale with the 800MHz Hypertransport link of Hammer doesn't make much sense. P4 FSB is 64 bit wide, bidirectional, carries memory traffic. Hypertransport links are 16 bits wide in each direction, unidirectional, don't carry memory traffic exept in SMP configs etc. If Digitimes is getting excited about the fact that they both run at 800MHz that seems a little silly.
Opteron tops out at 5.3Gbyte/s with dual 333MHz DDR channels. Springdale's memory subsystem will be at 5.3Gbyte/s with 333MHz DDR or 6.4Gbyte/s with 400MHz DDR. If Intel and the memory companies get the problems with DDR-400 sorted out then there will be little to stop AMD moving up to DDR-400 too.
Athlon 64 will of course only have half the bandwidth. However on the other hand it will have better latency, which for many apps is more useful.
I see that according to Anand software developers are being given 1.8GHz Hammers to play with now.