I dont understand how if 1MB bitcoin survives (as losing fork) how there will be a growing backlog of unconfirmed tx?
Because the transactions issued by clients are in principle executable in both branches. Only a few transactions will be specific to only one branch: namely, those that involve coins that were mined in that branch, after the split.
The incoming traffic is now ~120'000 transactions per day, on average. For the last 12 months it has grown almost linearly at ~5000 tx/day per month. If it continues growing at the same pace, by Jan/2016 it wil be ~150'000 tx/day. The effective capacity of the bitcoin mining network, revealed in the recent stress tests, is ~200'000 tx/day or ~1400 tx/block.
Suppose that the miners split 90:10 between the 8 MB and the 1 MB branches. The 8 MB branch will have ~130 blocks/day, which will have to carry ~1150 tx/block -- which is still less than the effective capacity ~1400 tx/block. There may be "traffic jams" at peak hours or peak days, but the backlogs should clear after a few hours at most.
On the other hand, the 1 MB branch will have ~15 blocks per day only. Each block would have to carry 10'000 tx, which is way over the capacity ~1400 tx/block. So, every 10 minutes, on average, 1400 tx will be confirmed, and 8600 tx will be added to the queue. The backlog will only begin to clear when the difficulty is readjusted and the block rate returns to ~10-15 min. The adjustment happens every 2100 blocks, with is normally 2 weeks but in that chain will be 20 weeks.
the XT miners will aggressively attack the original to kill it, then it seems the tyranny of the majority. To be able to make the real bitcoin into an altcoin.... I never imagined this would be possible
Well, right now the 5 largest miners (who have ~70% of all hashpower) could cooperate to starve all the other miners, and take 100% of the block rewards intead of just 70%. Or they could do much nastier things.
Let us not quibble over exact details, since it is not possible to predict exact amount. So using your numbers of 90/10 split:
"The backlog will only begin to clear when the difficulty is readjusted and the block rate returns to ~10-15 min. The adjustment happens every 2100 blocks, with is normally 2 weeks but in that chain will be 20 weeks."
OK, it is 6 months later and blocks are back to normalish rates. With all of the existing bitcoin infrastructure are you saying that it wont be a viable altcoin? That LTC is worth more than old bitcoin? That NMC is worth more then old bitcoin?
Did you consider that there are a lot of people that use bitcoin and if dont update to a new wallet and they see that they received an old bitcoin, maybe they just accept it. doesnt even the Mtgox bitcoins sell for amounts > $0?
To be so confident that multibillion dollars of existing value will just vanish within weeks, this just does not pass the common sense test.
James