As of right now, the best system to have intel on is the x38. but as alwyas intel has to find a way to try and kill us with offereing a new system and replace it by a newer system in less than 3 months of released.
As of what you can buy off the market the X38 offers excellent performance.
here are the good points of the x38
- The only chipset that offers DDR2 andDDR3
- offers 2 PCI-Express *16 ports
- Suports intel's 45nm architecture
the bad points
- going to be replaced early Q1 of next year with the x48 motherboard ( but this board so far only supports DDR3)
- pretty much an expensive board for one that will be extinct in less than 2 months. plus it's the first intel chipset that has it's lifetime shorten to 6 months by so called better hardware.
now that we have our processor the QX9650, the only excellent choice is the x38, but choosing this will mean that the only graphic card we can choose will be ati's HD38XX series ( mainly because of the built in support for crossfire, choosing nvdia is also possible but when the users wants more advance features for their hardware you be stuck with the x38).
As far as whihc mother board is the best here are your choices
gigabyte GA-X38T-DQ6
asus Maximus formula Extreme
ASUS P5E3 Deluxe
Foxconn X38A
MSI X38 Diamond
Now the gigabyte is an excelent motherboard, but it's only outstanding when you are overclocking, based on stock performance gigabyte is second to Asus. Asus for stock peroformance is the best, but they are the best cause thier stock settings are slight overclocks, there by putting them in the lead.
my choice will be between the Gigabye GA-X38T-DQ6 and the ASUS P5E3 Deluxe. the reason i chose the P5E3 Deluxe over the maximus formula extreme is for two reasons. the P5E3 Deluxe offers the most features out of box and any other competitor( provided you are interested in 802.11n built in, windows media center remote and IR controller) also the maximus forumula extreme is designed to work best with a water cooling setup.
Please note the Maximus formula extreme and the P5E3 are basically the same board . they just priced differently based on additional features.
Also tomshardware has a good analysis of the best board for DDR3 and the Asus won. here is a link for the review.
http://www.tomshardware.com/2007/11/26/x38_comparison_part2/index.html
also Anandtech give the board the extreme benchmarkers choice.
http://www.anandtech.com/mb/showdoc.aspx?i=3172&p=12