It will still be slower than the doubled-up GX2 but we are sure that two X1950 XTXes will beat the single 7950 GX2. It may even give quad SLI to run for its money.
The cards will surface in late August and should be available from launch. We know that they will use GDDR 4 and that will end up seven percent faster from the current X1900 XTX cards.
It will still need a Crossfire board but might have some other nice and cool features. We hear it will have a new cooler, to make it nice and quiet, for instance. µ