Intel Core i7 920, Core i7 965 EE

By Koushik Saha on 15.12.08

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Long awaited Nehalem architecture got its official name: Core i7. We have tested two CPUs based on this architecture along with one motherboard based on X58 chipset also signed by Intel. But let’s cut to the chase and go straight to testing and results.
New Chipset

Code name for X58 chipset is “Tylersburg”. This chipset is made in 65 nm manufacturing process and it is direct descendant of X48 chipset, which means that it belongs to Intel Extreme chipset series. There will be more than one version of X58 chipset: EP, EN and WS version that will be differentiated by number of PCI Express lines and QPI (QuickPath Interconnect) connections (links, busses). On server or WS (WorkStation) motherboards we can expect larger number of QPIs (used for I/O communication of integrated memory controller), while EP versions will have more PCI Express lines. Motherboards based on EP and EN versions of X58 chipset will be used more frequently than WS version. Weexpect that EP versions of X58 motherboards will have at least 3 PCI Express slots of which 2 slots will operate in x16 mode. Maybe the best detail of X58 chipset is that it will support CrossFire and SLI technologies.X58 chipset consists of two chips but MCH (Memory Controller Hub – memory controller) is integrated in CPU so there is no memory controller in NorthBridge. Because of that it is wrong to call it NorthBridge but many of us will continue to call it that way. Right name for that chip would be: I/O Hub, because almost only function of this chip is to connect CPU with PCI Express bus and SouthBridge. ICH10 or ICH10R (I/O Control Hub) is known from the past, and we encountered it for the first time on P45 chipset. Technical specifications are the same: 6 SATAII ports, two GB LAN controllers, 12 USB 2.0 ports, 6 PCI Express x1 slots, Intel HD audio etc. Real difference is existence of one PCI slot and no PATA connectors.At first sight Intel DX58SO is so different from any other tested motherboard and since we got technical sample we cannot comment on accessories that will be in retail package. Motherboard itself looks conservative and at the same time very contemporary. As you may already conclude, it is based on X58 chipset. This model belongs to Intel Extreme series of motherboards. Layout is drastically different from earlier models from this series. DDR3 memory slots are located on same positions as on legendary DFI NF4 LanParty Ultra-D model. There are 4 DIMM memory slots but it is not clear why Intel didn’t implement all 6 slots. Triple Channel mode for memory is achievable by inserting memory modules in blue colored DIMM slots. Fourth slot is almost useless in this configuration because it can be cause of problems with memory addressing (degradation of performances can occur), especially if we take into account integrated memory controller. Location of memory slots affected position of CPU socket that is located almost at the center of motherboard. Six-phase power unit is placed right beside CPU socket and mosfet transistors are covered with aluminum heat-spreaders. On the right are positioned 24-pin power connector and I/O Hub (IOH) that is also cooled by blue colored aluminum heat-spreader on which can be mounted 40mm transparent fan. This small fan is lighted by blue diodes and can be mounted thanks to supplied plastics clips. EPS12 connector has unusual location: at the middle of motherboard closer to right edge. We assume that this location is used because of closeness with CPU power unit so current will be more “ironed” and with less loss. Other components on motherboard have more or less standard positions.
Besides standard and many times seen options, most interesting options are those that are used for overclock. Overclock options can be found in “Processor Overrides” section while other important settings can be found in “BUS Overrides” and “Memory Overrides” sections. In BUS Overrides menu you can set voltage and basic speed of integrated memory controller and QPI bus. In Memory Overrides section can be found settings for all memory timings. Interesting detail is that only upon inserting Core i7 965 CPU we unlocked some of the options in Memory Overrides section. One of those “new” options were two additional multipliers for memory (10 and 12) besides “old” 6 and 8 values. After we plugged in “weaker” Core i7 920 CPU those options disappeared but despite that we managed to achieve stable clock for QPI of 195MHz which resulted in 3.9 GHz frequency for Core i7 920 CPU model. Very impressive! Unfortunately we didn’t manage to determine are those 195 MHz limit of motherboard or is it only for our CPU. The fact was that motherboard booted even on QPI set on 210 MHz but system was very unstable. Most surprising fact was that even with new BIOS (updated) motherboard didn’t allowed us to lower multiplier so we didn’t manage to test limits of QPI bus. Nor “regular” (920) nor EE (Extreme Edition – 965) Core i7 didn’t allowed us to lower multiplier so we think that it is “fresh” BIOS to be blamed for that and the hope remains that this “bug” will be ironed in next BIOS version.

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