Loan-to-Value (LTV) is the ratio of deposited assets over borrowed assets, representing the percentage of the collateral of a loan.
LTV (%) = (borrows / deposits) * 100
The amount of deposits and borrows of each boost are determined by your initial deposit amount, but the LTV for each asset is always fixed. For example, if your initial deposit is 100 ETH and your boost is 4X, your total deposit is 400 ETH and total borrow is 300 ETH — 75% LTV. If your initial deposit is 1,000 ETH and boost is 4X, your total deposit is 4,000 ETH and total borrow is 3000 ETH — equally 75% LTV.
The maximum level of boost per each asset is determined by the collateral ratio. The LTV of ETH is 75%, so the maximum boost level of ETH is 4X. The LTV of LINK is 60%, so the maximum boost level of LINK is 2.5X.