975X vs P965
As far as Intel is concerned, P965 is officially their ďmainstreamĒ chipset, while 975X is their high-end chipset for enthusiasts. But in a lot of ways, P965 is the more forward-looking platform thatís built for the high-end crowd.
One of the most notable examples of this is found in the chipsetís North Bridge. Whereas the memory controller found in 975X is limited to memory speeds of just 667MHz, the P965 chipset supports not only DDR2-667, but also 800MHz DDR2 memory as well. DDR2-800 is capable of delivering 2.1GB/sec of additional memory bandwidth to the system. Peak bandwidth goes from 10.7GB/sec in 975X to 12.8GB/sec in P965. About a month ago we ran some tests with a Core 2 Extreme and Core 2 Duo E6700 equipped with both DDR2-667 and DDR2-800 and found the faster memory provided an additional 2-4% in performance in games, while DDR2-800 shaved a few seconds off our DivX conversion and WME 9 tests in our media encoding testing.
Where P965 really excels in comparison to 975X though is in its South Bridge. Intelís outfitted P965 with their brand new ICH8 South Bridge, 975X was built around Intelís older ICH7 South Bridge. ICH8 has a few new features going for it that arenít found in ICH7.
For starters, ICH8 supports more Serial ATA drives than ICH7, six in ICH8 versus just four in ICH7 (each supporting 3Gb/sec SATA). In fact, with the new South Bridge Intel emphasizes Serial ATA storage, as the chipset doesnít support parallel ATA drives. Intelís been deemphasizing parallel ATA for some time now: whereas five years ago all chipsets supported up to four parallel ATA devices (via two controllers) starting with their ICH6 South Bridge in mid-2004 Intelís only supported up to two parallel ATA devices (via one controller). With the new ICH, Intelís clearly trying to move the industry from PATA to SATA, although unfortunately optical drive manufacturers are still being reluctant to embrace the SATA interface Ė even the first generation of Blu-ray disc drives and HD-DVD drives all rely on PATA. Fortunately motherboard manufacturers like Gigabyte realize this and are including PATA support on their P965 motherboards via an external controller.
Another key difference between ICH7 and ICH8 is USB support. The newer ICH8 South Bridge supports up to ten USB 2.0 ports, whereas ICH7 is limited to eight.
Despite these positives in favor of P965, it does have one glaring deficiency for enthusiasts: lack of support for multi-GPU solutions like ATIís CrossFire technology. While there are P965 motherboards on the market with two PCI Express graphics slots, including Gigabyteís own GA-965P-DQ6, the chipset doesnít support CrossFire or SLI. Instead the idea is that you can connect a second PCI Express graphics card to drive additional LCD or CRT displays. Itís a little deceiving if youíre a gamer who had his heart set on transferring his CrossFire or SLI setup to Core 2, but keep in mind that itís a limitation of the system chipset, not the motherboard.
Other than these key differences, the P965 and 975X chipsets are pretty similar, both chipsets support bus speeds of 1,066MHz, 800MHz, and 533MHz, up to six x1 PCI Express devices, Intel High Definition audio and Matrix Storage technology, as well as Gigabit Ethernet networking. Performance between the two chipsets is similar as well, in fact the GA-965P-DQ6 outperformed 975X motherboards in some of our tests.