All three teams entering round 5 with a 4-0 score drew their matches, and a bunch of others caught them at the top. Right now seven teams have 4.5/5 (or rather, 9/10, since the official scoring uses 2-1-0 rather than 1-.5-0); in tiebreak order they are Azerbaijan, Serbia, Kazakhstan, Bulgaria, Cuba, Uzbekistan and Georgia. No less than 17 other teams are right behind them at 4/5 (or 8/10), including main contenders Russia, France, China and Armenia, but also surprises like Indonesia, Norway's B team, and Iran! Norway's A team has 7/10, along with the USA, Greece, Italy (Caruana et al), Israel (Gelfand et al), Ukraine (Ivanchuk et al) and many more. Not much stratification has occurred yet.
In the women's event China, Hungary and Russia remain perfect; the Netherlands, Poland and Serbia all have 9/10, and then there are 12 more teams at 8, including the USA and Greece. Bravo Hellas!
As the top teams are already facing off there were some real highlights on the day, most notably one-on-one battles between Levon Aronian and Magnus Carlsen and between Vladimir Kramnik and Veselin Topalov. In the first game Aronian was up a pawn for most of the game, but never with any serious winning chances. Still, it was probably nice to press, and in the end his team won - the most important thing.
As for the hatefest between Kramnik and Topalov, Kramnik played what Garry Kasparov labeled a "great game", and he (Kramnik) certainly enjoyed discussing the game afterwards (with a bit of occasional gleeful malice) with the commentators. His pleasure was in good part spoiled however by the Russian team's failure to win the match. The culprit was Sergey Karjakin's blunders against Valentin Iotov. The most obvious one was his failure to recapture on d5 with the bishop on move 27. He apparently thought he could build up more and then take, but the problem with taking later was that Black would win by sacrificing the exchange on d5 and playing ...f4, when the threat of ...Qh2# would win the game. That wasn't a worry on move 27: 27.Bxd5 Rxd5 28.cxd5 Qf4 and now White returns the exchange with 29.Rxe5, and he'll have no problems. Karjakin may be even more upset when he learns that he could have won the game practically in the opening with 14.Qa3! The knight on e4 can't be taken because of 15.Qe7#, 14...Bxg5 is met by 15.Nd6+ Kd8 16.Nxf7+, and meanwhile the threat of 15.Bxf4 followed by 16.Nd6+ forces Black to cough up a pawn without a shred of compensation (in fact, White will have the better position to go along with the extra pawn).
Another high-profile blunder cost another of the pre-tournament favorites a crucial point in the standings. The Ukraine-Uzbekistan match was headed for a draw, but an out-of-form Vassily Ivanchuk blundered in time trouble and lost to Rustam Kasimdzhanov from what Kasparov had considered a "dead drawn" position. Errare humanum est!