diff --git a/invoice_speedup.diff b/invoice_speedup.diff
new file mode 100644
index 0000000..3a11ae4
--- /dev/null
+++ b/invoice_speedup.diff
@@ -0,0 +1,514 @@
+diff -r 3681a54fda0a trytond/trytond/modules/account_invoice/invoice.py
+--- a/trytond/trytond/modules/account_invoice/invoice.py	Tue Jul 07 16:46:50 2015 +0200
++++ b/trytond/trytond/modules/account_invoice/invoice.py	Tue Jul 07 17:12:14 2015 +0200
+@@ -944,33 +944,35 @@
+         '''
+         Return move line
+         '''
+-        Currency = Pool().get('currency.currency')
+-        res = {}
++        pool = Pool()
++        Currency = pool.get('currency.currency')
++        MoveLine = pool.get('account.move.line')
++        line = MoveLine()
+         if self.currency.id != self.company.currency.id:
+             with Transaction().set_context(date=self.currency_date):
+-                res['amount_second_currency'] = Currency.compute(
++                line.amount_second_currency = Currency.compute(
+                     self.company.currency, amount, self.currency)
+-            res['amount_second_currency'] = abs(res['amount_second_currency'])
+-            res['second_currency'] = self.currency.id
++            line.amount_second_currency = abs(line.amount_second_currency)
++            line.second_currency = self.currency.id
+         else:
+-            res['amount_second_currency'] = None
+-            res['second_currency'] = None
++            line.amount_second_currency = None
++            line.second_currency = None
+         if amount >= Decimal('0.0'):
+-            res['debit'] = Decimal('0.0')
+-            res['credit'] = amount
++            line.debit = Decimal('0.0')
++            line.credit = amount
+         else:
+-            res['debit'] = - amount
+-            res['credit'] = Decimal('0.0')
+-        res['account'] = self.account.id
++            line.debit = - amount
++            line.credit = Decimal('0.0')
++        line.account = self.account.id
+         if self.account.party_required:
+-            res['party'] = self.party.id
+-        res['maturity_date'] = date
+-        res['description'] = self.description
+-        return res
++            line.party = self.party.id
++        line.maturity_date = date
++        line.description = self.description
++        return line
+
+-    def create_move(self):
++    def get_move(self):
+         '''
+-        Create account move for the invoice and return the created move
++        Compute account move for the invoice and return the created move
+         '''
+         pool = Pool()
+         Move = pool.get('account.move')
+@@ -986,10 +988,10 @@
+         total = Decimal('0.0')
+         total_currency = Decimal('0.0')
+         for line in move_lines:
+-            total += line['debit'] - line['credit']
+-            if line['amount_second_currency']:
+-                total_currency += line['amount_second_currency'].copy_sign(
+-                    line['debit'] - line['credit'])
++            total += line.debit - line.credit
++            if line.amount_second_currency:
++                total_currency += line.amount_second_currency.copy_sign(
++                    line.debit - line.credit)
+
+         term_lines = self.payment_term.compute(total, self.company.currency,
+             self.invoice_date)
+@@ -997,28 +999,23 @@
+         if not term_lines:
+             term_lines = [(Date.today(), total)]
+         for date, amount in term_lines:
+-            val = self._get_move_line(date, amount)
+-            if val['amount_second_currency']:
+-                remainder_total_currency += val['amount_second_currency']
+-            move_lines.append(val)
++            line = self._get_move_line(date, amount)
++            if line.amount_second_currency:
++                remainder_total_currency += line.amount_second_currency
++            move_lines.append(line)
+         if not self.currency.is_zero(remainder_total_currency):
+-            move_lines[-1]['amount_second_currency'] -= \
++            move_lines[-1].amount_second_currency -= \
+                 remainder_total_currency
+-
+         accounting_date = self.accounting_date or self.invoice_date
+         period_id = Period.find(self.company.id, date=accounting_date)
+
+-        move, = Move.create([{
+-                    'journal': self.journal.id,
+-                    'period': period_id,
+-                    'date': accounting_date,
+-                    'origin': str(self),
+-                    'company': self.company.id,
+-                    'lines': [('create', move_lines)],
+-                    }])
+-        self.write([self], {
+-                'move': move.id,
+-                })
++        move = Move()
++        move.journal = self.journal
++        move.period = period_id
++        move.date = accounting_date
++        move.origin = self
++        move.company = self.company
++        move.lines = move_lines
+         return move
+
+     def set_number(self):
+@@ -1050,11 +1047,10 @@
+         with Transaction().set_context(
+                 date=self.invoice_date or Date.today()):
+             number = Sequence.get_id(sequence.id)
+-            vals = {'number': number}
++            self.number = number
+             if (not self.invoice_date
+                     and self.type in ('out_invoice', 'out_credit_note')):
+-                vals['invoice_date'] = Transaction().context['date']
+-        self.write([self], vals)
++                self.invoice_date = Transaction().context['date']
+
+     @classmethod
+     def check_modify(cls, invoices):
+@@ -1308,26 +1304,18 @@
+         '''
+         Return values to credit invoice.
+         '''
+-        res = {}
+-        res['type'] = _CREDIT_TYPE[self.type]
+-
+-        for field in ('description', 'comment'):
+-            res[field] = getattr(self, field)
++        credit = self.__class__()
++        credit.type = _CREDIT_TYPE[self.type]
+
+         for field in ('company', 'party', 'invoice_address', 'currency',
+-                'journal', 'account', 'payment_term'):
+-            res[field] = getattr(self, field).id
++                'journal', 'account', 'payment_term', 'description',
++                'comment'):
++            setattr(credit, field, getattr(self, field))
+
+-        res['lines'] = []
+-        if self.lines:
+-            res['lines'].append(('create',
+-                    [line._credit() for line in self.lines]))
++        credit.lines = [line._credit() for line in self.lines]
+
+-        res['taxes'] = []
+-        to_create = [tax._credit() for tax in self.taxes if tax.manual]
+-        if to_create:
+-            res['taxes'].append(('create', to_create))
+-        return res
++        credit.taxes = [tax._credit() for tax in self.taxes if tax.manual]
++        return credit
+
+     @classmethod
+     def credit(cls, invoices, refund=False):
+@@ -1337,18 +1325,17 @@
+         '''
+         MoveLine = Pool().get('account.move.line')
+
+-        new_invoices = []
+-        for invoice in invoices:
+-            new_invoice, = cls.create([invoice._credit()])
+-            new_invoices.append(new_invoice)
+-            if refund:
+-                cls.post([new_invoice])
++        new_invoices = [i._credit() for i in invoices]
++        new_invoices = cls.create([i._save_values for i in new_invoices])
++        cls.update_taxes(new_invoices)
++        if refund:
++            cls.post(new_invoices)
++            for invoice, new_invoice in itertools.izip(invoices, new_invoices):
+                 if new_invoice.state == 'posted':
+                     MoveLine.reconcile([l for l in invoice.lines_to_pay
+                             if not l.reconciliation] +
+                         [l for l in new_invoice.lines_to_pay
+                             if not l.reconciliation])
+-        cls.update_taxes(new_invoices)
+         return new_invoices
+
+     @classmethod
+@@ -1368,10 +1355,16 @@
+     @ModelView.button
+     @Workflow.transition('validated')
+     def validate_invoice(cls, invoices):
++        to_write = []
+         for invoice in invoices:
+             if invoice.type in ('in_invoice', 'in_credit_note'):
+                 invoice.set_number()
+-                invoice.create_move()
++                move = invoice.get_move()
++                if move != invoice.move:
++                    invoice.move = invoice.get_move()
++                to_write.extend(([invoice], invoice._save_values))
++        if to_write:
++            cls.write(*to_write)
+
+     @classmethod
+     @ModelView.button
+@@ -1379,14 +1372,18 @@
+     def post(cls, invoices):
+         Move = Pool().get('account.move')
+
+-        moves = []
++        to_write = []
+         for invoice in invoices:
+             invoice.set_number()
+-            moves.append(invoice.create_move())
+-        cls.write([i for i in invoices if i.state != 'posted'], {
+-                'state': 'posted',
+-                })
+-        Move.post([m for m in moves if m.state != 'posted'])
++            move = invoice.get_move()
++            if move != invoice.move:
++                invoice.move = move
++            to_write.extend(([invoice], invoice._save_values))
++
++        if to_write:
++            cls.write(*to_write)
++        cls.write(invoices, {'state': 'posted'})
++        Move.post([i.move for i in invoices if i.move.state != 'posted'])
+         for invoice in invoices:
+             if invoice.type in ('out_invoice', 'out_credit_note'):
+                 invoice.print_invoice()
+@@ -1425,14 +1422,17 @@
+
+         cancel_moves = []
+         delete_moves = []
++        to_write = []
+         for invoice in invoices:
+             if invoice.move:
+                 if invoice.move.state == 'draft':
+                     delete_moves.append(invoice.move)
+                 elif not invoice.cancel_move:
+                     invoice.cancel_move = invoice.move.cancel()
+-                    invoice.save()
+                     cancel_moves.append(invoice.cancel_move)
++            to_write.extend(([invoice], invoice._save_values))
++        if to_write:
++            cls.write(*to_write)
+         if delete_moves:
+             Move.delete(delete_moves)
+         if cancel_moves:
+@@ -2000,6 +2000,7 @@
+         pool = Pool()
+         Tax = pool.get('account.tax')
+         Currency = pool.get('currency.currency')
++        TaxLine = pool.get('account.tax.line')
+
+         context = self.invoice.get_tax_context()
+         res = []
+@@ -2022,79 +2023,76 @@
+                         date=self.invoice.currency_date):
+                     amount = Currency.compute(self.invoice.currency,
+                         amount, self.invoice.company.currency)
+-                res.append({
+-                        'code': base_code_id,
+-                        'amount': amount,
+-                        'tax': tax['tax'].id if tax['tax'] else None,
+-                        })
++                tax_line = TaxLine()
++                tax_line.code = base_code_id
++                tax_line.amount = amount
++                tax_line.tax = tax['tax']
++                res.append(tax_line)
+         return res
+
+     def get_move_line(self):
+         '''
+-        Return a list of move lines values for invoice line
++        Return a list of move lines instances for invoice line
+         '''
+-        Currency = Pool().get('currency.currency')
+-        res = {}
++        pool = Pool()
++        Currency = pool.get('currency.currency')
++        MoveLine = pool.get('account.move.line')
+         if self.type != 'line':
+             return []
+-        res['description'] = self.description
++        line = MoveLine()
++        line.description = self.description
+         if self.invoice.currency != self.invoice.company.currency:
+             with Transaction().set_context(date=self.invoice.currency_date):
+                 amount = Currency.compute(self.invoice.currency,
+                     self.amount, self.invoice.company.currency)
+-            res['amount_second_currency'] = self.amount
+-            res['second_currency'] = self.invoice.currency.id
++            line.amount_second_currency = self.amount
++            line.second_currency = self.invoice.currency.id
+         else:
+             amount = self.amount
+-            res['amount_second_currency'] = None
+-            res['second_currency'] = None
++            line.amount_second_currency = None
++            line.second_currency = None
+         if self.invoice.type in ('in_invoice', 'out_credit_note'):
+             if amount >= Decimal('0.0'):
+-                res['debit'] = amount
+-                res['credit'] = Decimal('0.0')
++                line.debit = amount
++                line.credit = Decimal('0.0')
+             else:
+-                res['debit'] = Decimal('0.0')
+-                res['credit'] = - amount
+-                if res['amount_second_currency']:
+-                    res['amount_second_currency'] = \
+-                        - res['amount_second_currency']
++                line.debit = Decimal('0.0')
++                line.credit = -amount
++                if line.amount_second_currency:
++                    line.amount_second_currency = \
++                        - line.amount_second_currency
+         else:
+             if amount >= Decimal('0.0'):
+-                res['debit'] = Decimal('0.0')
+-                res['credit'] = amount
+-                if res['amount_second_currency']:
+-                    res['amount_second_currency'] = \
+-                        - res['amount_second_currency']
++                line.debit = Decimal('0.0')
++                line.credit = amount
++                if line.amount_second_currency:
++                    line.amount_second_currency = \
++                        - line.amount_second_currency
+             else:
+-                res['debit'] = - amount
+-                res['credit'] = Decimal('0.0')
+-        res['account'] = self.account.id
++                line.debit = -amount
++                line.credit = Decimal('0.0')
++        line.account = self.account.id
+         if self.account.party_required:
+-            res['party'] = self.invoice.party.id
++            line.party = self.invoice.party.id
+         computed_taxes = self._compute_taxes()
+         if computed_taxes:
+-            res['tax_lines'] = [('create', [tax for tax in computed_taxes])]
+-        return [res]
++            line.tax_lines = computed_taxes
++        return [line]
+
+     def _credit(self):
+         '''
+         Return values to credit line.
+         '''
+-        res = {}
+-        res['invoice_type'] = _CREDIT_TYPE[self.invoice_type]
+-        res['origin'] = str(self)
++        credit = self.__class__()
++        credit.invoice_type = _CREDIT_TYPE[self.invoice_type]
++        credit.origin = self
+
+         for field in ('sequence', 'type', 'quantity', 'unit_price',
+-                'description'):
+-            res[field] = getattr(self, field)
++                'description', 'unit', 'product', 'account'):
++            setattr(credit, field, getattr(self, field))
+
+-        for field in ('unit', 'product', 'account'):
+-            res[field] = getattr(getattr(self, field), 'id', None)
+-
+-        res['taxes'] = []
+-        if self.taxes:
+-            res['taxes'].append(('add', [tax.id for tax in self.taxes]))
+-        return res
++        credit.taxes = self.taxes
++        return credit
+
+
+ class InvoiceLineTax(ModelSQL):
+@@ -2290,67 +2288,67 @@
+
+     def get_move_line(self):
+         '''
+-        Return a list of move lines values for invoice tax
++        Return a list of move lines instances for invoice tax
+         '''
+-        Currency = Pool().get('currency.currency')
+-        res = {}
++        pool = Pool()
++        Currency = pool.get('currency.currency')
++        MoveLine = pool.get('account.move.line')
++        TaxLine = pool.get('account.tax.line')
++        line = MoveLine()
+         if not self.amount:
+             return []
+-        res['description'] = self.description
++        line.description = self.description
+         if self.invoice.currency != self.invoice.company.currency:
+             with Transaction().set_context(date=self.invoice.currency_date):
+                 amount = Currency.compute(self.invoice.currency, self.amount,
+                     self.invoice.company.currency)
+-            res['amount_second_currency'] = self.amount
+-            res['second_currency'] = self.invoice.currency.id
++            line.amount_second_currency = self.amount
++            line.second_currency = self.invoice.currency.id
+         else:
+             amount = self.amount
+-            res['amount_second_currency'] = None
+-            res['second_currency'] = None
++            line.amount_second_currency = None
++            line.second_currency = None
+         if self.invoice.type in ('in_invoice', 'out_credit_note'):
+             if amount >= Decimal('0.0'):
+-                res['debit'] = amount
+-                res['credit'] = Decimal('0.0')
++                line.debit = amount
++                line.credit = Decimal('0.0')
+             else:
+-                res['debit'] = Decimal('0.0')
+-                res['credit'] = - amount
+-                if res['amount_second_currency']:
+-                    res['amount_second_currency'] = \
+-                        - res['amount_second_currency']
++                line.debit = Decimal('0.0')
++                line.credit = -amount
++                if line.amount_second_currency:
++                    line.amount_second_currency = \
++                        - line.amount_second_currency
+         else:
+             if amount >= Decimal('0.0'):
+-                res['debit'] = Decimal('0.0')
+-                res['credit'] = amount
+-                if res['amount_second_currency']:
+-                    res['amount_second_currency'] = \
+-                        - res['amount_second_currency']
++                line.debit = Decimal('0.0')
++                line.credit = amount
++                if line.amount_second_currency:
++                    line.amount_second_currency = \
++                        - line.amount_second_currency
+             else:
+-                res['debit'] = - amount
+-                res['credit'] = Decimal('0.0')
+-        res['account'] = self.account.id
++                line.debit = -amount
++                line.credit = Decimal('0.0')
++        line.account = self.account.id
+         if self.account.party_required:
+-            res['party'] = self.invoice.party.id
++            line.party = self.invoice.party.id
+         if self.tax_code:
+-            res['tax_lines'] = [('create', [{
+-                            'code': self.tax_code.id,
+-                            'amount': amount * self.tax_sign,
+-                            'tax': self.tax and self.tax.id or None
+-                            }])]
+-        return [res]
++            tax_line = TaxLine()
++            tax_line.code = self.tax_code
++            tax_line.amount = amount * self.tax_sign
++            tax_line.tax = self.tax
++            line.tax_lines = [tax_line]
++        return [line]
+
+     def _credit(self):
+         '''
+         Return values to credit tax.
+         '''
+-        res = {}
+-
++        credit = self.__class__()
+         for field in ('description', 'sequence', 'base', 'amount',
+-                'manual', 'base_sign', 'tax_sign'):
+-            res[field] = getattr(self, field)
+-
+-        for field in ('account', 'base_code', 'tax_code', 'tax'):
+-            res[field] = getattr(self, field).id
+-        return res
++                'manual', 'base_sign', 'tax_sign', 'account', 'base_code',
++                'tax_code', 'tax'):
++            setattr(credit, field, getattr(self, field))
++        return credit
+
+
+ class PrintInvoiceWarning(ModelView):
+diff -r 0e69764f2826 trytond/trytond/modules/account_payment_type/invoice.py
+--- a/trytond/trytond/modules/account_payment_type/invoice.py	Tue Jul 07 10:10:50 2015 +0200
++++ b/trytond/trytond/modules/account_payment_type/invoice.py	Tue Jul 07 17:06:02 2015 +0200
+@@ -51,7 +51,7 @@
+         return res
+
+     def _get_move_line(self, date, amount):
+-        res = super(Invoice, self)._get_move_line(date, amount)
++        line = super(Invoice, self)._get_move_line(date, amount)
+         if self.payment_type:
+-            res['payment_type'] = self.payment_type
+-        return res
++            line.payment_type = self.payment_type
++        return line
+diff -r 6429c9c53cb8 trytond/trytond/modules/account_bank/account.py
+--- a/trytond/trytond/modules/account_bank/account.py	Tue May 05 14:36:02 2015 +0200
++++ b/trytond/trytond/modules/account_bank/account.py	Tue Jul 07 15:36:26 2015 +0200
+@@ -179,10 +179,10 @@
+         '''
+         Add account bank to move line when post invoice.
+         '''
+-        res = super(Invoice, self)._get_move_line(date, amount)
++        line = super(Invoice, self)._get_move_line(date, amount)
+         if self.bank_account:
+-            res['bank_account'] = self.bank_account
+-        return res
++            line.bank_account = self.bank_account
++        return line
+
+     @classmethod
+     def create(cls, vlist):
diff --git a/series b/series
index 5dad8e2..bd26b40 100644
--- a/series
+++ b/series
@@ -56,3 +56,4 @@ issue13181002_1.diff
 issue13211002_190001.diff
 issue17281002_20001.diff
 issue20301003_1.diff
+invoice_speedup.diff