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Gigabyte & Foxconn AMD 790GX Motherboards |
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Written by Fedja Drndarski
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Wednesday, 10 September 2008 |
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Page 1 of 7
 It’ s been a while since AMD-ATi Company introduced, so far the best integrated chipset – AMD RS780 i.e. AMD780G which surpassed, by performances of integrated graphics and by quality of video display, its competition. nVIDIA soon after introduced its 780a chipset that offered support for SLi and didn’t fall much behind AMD/ATi RS780. Comparing to AMD RS780, nf780a is attended for more expensive motherboards that are equipped with better and more quality electronics.
But, motherboards with RS780 couldn’t go hand in hand with specifications of “hot” quad core Phenom processors (dissipation is up to 140W) and it often happened that cheap 780G motherboard in combination with such a processor broke down in guarantee time period. That’s why some manufacturers integrated additional cooling of power unit while the others waited launching of newer and better high-end 790GX chipset and they didn’t give guarantee for 780G if you were using it with 125W or more powerful Phenom X4 processor.
AMD 790GX Chipset
New chipset is attended for enthusiasts’ motherboards. 790GX is mainly equipped with sideport 128MB DDR3 memory at 1333MHz. Similar option existed for some 780G motherboards but only few manufacturers implemented this possibility into their first 780G motherboard models. 790GX brings 30% better graphics performances from its predecessor. With this graphics it’s possible to play most of new game titles, of course in lower resolution with medium or low settings. Popular Crysis in 800x600 gives quite respectable 23fps on medium settings!
790GX is designed with goal to provide better performances with Phenom processors, or more precise, better overclock, and to achieve much better as possible, multimedia enjoyment for reasonable price. AMD take care of all of that and even more - energy efficiency. New chipset warms up less and it’s built in 55nm TSMC technology process. Supported technologies are: CrossFireX, Hybrid Graphics, Native HD Format Acceleration, RAID … Important novelty is new SB750 southbridge that brings so called ACC – Advanced Clock Calibration.
Thanks to calibrated geometry of clock signal, communication of CPU and the rest of system have much better ratio signal-noise and therefore system works more stabile during overclock (oc. margin increases from previous 3GHz to much higher clocks). Frankly, there were manufacturers like DFI that managed to made motherboards with old chipset that could pull out from processors more than 3.2GHz but those where different class of product.
With 790GX, arrives new AMD Overdrive Utility which allows, beside settings for calibration of clock signal, overclock of integrated GPU and SidePort memory.
ATi Hybrid CrossFire allows creation of CrossFire system between integrated GPU and graphics card. For example, HD3470 in combination with 790GX chipset will have performances like HD3670 on some other motherboard without Hybrid CrossFire.
AMD 790GX has 26 PCI-e 2.0 lines but 4 of them are meant for interconnections of chipset, so actually 22 PCI-e 2.0 lines are available for graphics cards and other peripheral devices, and that amount is still for 4 more from number of PCI-e lines that nForce 750a chipset supports.
Optimization in field of energy power saving is story for itself. Consumption is reduced for 12W in idle and this is result of implemented C1E Power State. In this state, Phenom doesn’t perform instructions but it can easily become active and start performing instructions. The difference is that C1E doesn’t use “halt” instruction like C1. C1E is controlled by BIOS without turning on ACPI (Advanced Configuration Power-Management Interface) consumption control. In other words, processor in idle will work in low temperatures and low power consumption even outside of Windows surroundings (Windows supports ACPI).
SB750 beside ACC technology brings support for total of 6 SATA-2 ports and even 12USB ports. HD audio, 1 Parallel ATA channel and of course old PCI interface are also supported. New SB supports RAID 5. Unfortunately, problems with AHCI Serial ATA controller are present also in SB750 southbridge, so SATA devices will work in standard IDE mode that doesn’t support advanced technologies like Native Command Queuing and Hot Swap.
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