While an increasing number of games are able to take advantage of four processor cores, outside of the professional video production and 3D animation/rendering industry, there are very few applications that can take advantage of eight CPU cores.
However, this didn't stop Intel producing Skulltrail, an octo-core gaming platform. With support for both CrossFire and SLI, plus the ability to overclock two quad-core CPUs, the theory behind Skulltrail was that rather than having a separate octo-core system for work and another dual- or quad-core PC for gaming, you could use a single all-powerful PC for everything. The end result was a partnership between two products, the Intel D5400XS motherboard and a pair of LGA771 Core 2 Extreme QX9775 CPUs.
The QX9775 is a halfway house between the LGA775 Core 2 Extreme QX9770 and the LGA771 Xeon X5482. While its uses the same LGA771 packaging as the Xeon X5482, its pre-fetchers are optimised for consumer apps and games, rather than workstation and server apps. Each of the CPU's four cores are clocked at 3.2GHz, and as they're branded as Extreme edition CPUs, they're multiplier unlocked.
Due to its high-frequency CPUs, a Skulltrail system tears through most benchmarks, even though few consumer apps can take advantage of all eight cores. While its score of 20,161 in Cinebench is unmatched, its score of 2,200 in our video encoding test, which effectively uses five or six cores, is midway between those of the cheaper Core i7-920 and 940. Although you can install up to four graphics cards in the D5400XS, its slow FBDIMM memory means that it's slower than the QX9770, high-end Core 2 Duos and Core i7s in games.
By raising the vcore of both CPUs to 1.5V, we managed to overclock them from 3.2GHz to 4.2GHz. This significantly boosted the system's performance in most benchmarks, resulting in a record-breaking score of 26,099 in Cinebench. However, Flight Simulator X refused to budge above a dire 10fps, even when overclocked.
While the pair of QX9775s retain their crown in heavily multithreaded tasks such as 3D rendering, with the advent of the Core i7-series, Skulltrail is no longer a good purchase. Hardcore gamers would be better off buying a cheaper Core 2 Duo or Core i7, although 3D professionals who also enjoy gaming on the side may want to wait until Intel releases its Nehalem-based Xeons in a few months. Skulltrail II may even be on its way soon.
Author: James Gorbold & Antony Leather
Intel Core 2 Extreme (LGA771)