I only connect to a known host so I trust everything that comes from it. What can I remove in order to speed up the initial sync with the blockchain?

I have already commented out a few things in CheckBlock (main.cpp). My version looks like this now:

Code:

bool CheckBlock(const CBlock& block, CValidationState& state, bool fCheckPOW, bool fCheckMerkleRoot)
{
// These are checks that are independent of context
// that can be verified before saving an orphan block.
/*
// Size limits
if (block.vtx.empty() || block.vtx.size() > MAX_BLOCK_SIZE || ::GetSerializeSize(block, SER_NETWORK, PROTOCOL_VERSION) > MAX_BLOCK_SIZE)
return state.DoS(100, error("CheckBlock() : size limits failed"),
REJECT_INVALID, "bad-blk-length");

// Check proof of work matches claimed amount
if (fCheckPOW && !CheckProofOfWork(block.GetHash(), block.nBits))
return state.DoS(50, error("CheckBlock() : proof of work failed"),
REJECT_INVALID, "high-hash");
*/

// Check timestamp
if (block.GetBlockTime() > GetAdjustedTime() + 2 * 60 * 60)
return state.Invalid(error("CheckBlock() : block timestamp too far in the future"),
REJECT_INVALID, "time-too-new");
/*
// First transaction must be coinbase, the rest must not be
if (block.vtx.empty() || !block.vtx[0].IsCoinBase())
return state.DoS(100, error("CheckBlock() : first tx is not coinbase"),
REJECT_INVALID, "bad-cb-missing");
for (unsigned int i = 1; i < block.vtx.size(); i++)
if (block.vtx[i].IsCoinBase())
return state.DoS(100, error("CheckBlock() : more than one coinbase"),
REJECT_INVALID, "bad-cb-multiple");
*/

/*
// Check transactions
BOOST_FOREACH(const CTransaction& tx, block.vtx)
if (!CheckTransaction(tx, state))
return error("CheckBlock() : CheckTransaction failed");
*/

// Build the merkle tree already. We need it anyway later, and it makes the
// block cache the transaction hashes, which means they don't need to be
// recalculated many times during this block's validation.
block.BuildMerkleTree();

// Check for duplicate txids. This is caught by ConnectInputs(),
// but catching it earlier avoids a potential DoS attack:
set uniqueTx;
for (unsigned int i = 0; i < block.vtx.size(); i++) {
uniqueTx.insert(block.GetTxHash(i));
}
if (uniqueTx.size() != block.vtx.size())
return state.DoS(100, error("CheckBlock() : duplicate transaction"),
REJECT_INVALID, "bad-txns-duplicate", true);

/*
unsigned int nSigOps = 0;
BOOST_FOREACH(const CTransaction& tx, block.vtx)
{
nSigOps += GetLegacySigOpCount(tx);
}
if (nSigOps > MAX_BLOCK_SIGOPS)
return state.DoS(100, error("CheckBlock() : out-of-bounds SigOpCount"),
REJECT_INVALID, "bad-blk-sigops", true);

// Check merkle root
if (fCheckMerkleRoot && block.hashMerkleRoot != block.vMerkleTree.back())
return state.DoS(100, error("CheckBlock() : hashMerkleRoot mismatch"),
REJECT_INVALID, "bad-txnmrklroot", true);
*/

return true;
}

What other changes can I do to speed it up?