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Old October 17, 2008, 09:22 AM
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3oh6 3oh6 is offline
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Location: Edmonton, AB
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Default First Course Continued: 2x2GB Memory Clocking

We will now focus on a 2GB kit of memory that absolutely tore it up on the 790i Ultra, a kit of Mushkin Ascent 2x2GB PC3-12800 CL7. After seeing the 2x1GB kit held back by the SPP, it will be interesting to see if these 2x2gb modules struggle at the higher clocks. Keep in mind, this kit ran up to and over DDR3-2000 dual 32M at 8-7-6 fairly easily. Here is a repeat of the setup used in testing:
  • CPU: Intel C2D E8400 (L808A476)
  • CPU Cooling: Thermalright Ultra-120
  • RAM: Mushkin Ascent 2x2GB PC3-128000 CL7
  • NB Cooling: Stock
  • SB Cooling: Stock
  • PWM Cooling: Stock
  • GPU: HIS HD3870X2
  • PSU: Thermaltake Pure Power 750W
  • HD: Seagate SATAII 80GB 8MB NCQ
  • OS: Windows XP Pro x64 SP2 (fully updated)
Before we see any results, here is a quick look at the setup which is un-changed from the FSB Out of the Box clocking section.

The setup as tested...
click for full size...

With no SPP volt mod or additional cooling to the chipset, we saw 2x1GB clocks being limited by the BIOS selectable vSPP. With a 2x2GB kit populating the DIMM slots now, I fully expect to see the same type of situation...but unfortunately, a little sooner in the clocks.

As suspected, memory clocks were held back by the SPP voltage maximum that can be set in the BIOS. This 790i SLI just isn't ready to play with the big boys right out of the box, it needs a little help. These modules have a lot more in them as proven by what they did on a modded and cooled 790i Ultra, but this board just can't get that out of them in stock form. On both the 2x1GB kit and more pronounced with this 2x2GB kit, CL7 clocks suffer the most. It appears that the CL7 clocking ability, or slight weakness in ability, of the 790i SLI chipset holds true from my 790i Ultra experience. The board should have no problem running any kit of memory available at just won't be breaking records without the appropriate renovations to the board.

NVIDIA 790i:
Click link for full size screenshot...
6-6-5-X 1T/2T: 775MHz :: 1.90v | 815MHz :: 2.00v | 850MHz :: 2.10v

7-6-5-X 2T: 895MHz :: 1.90v | 915MHz :: 2.00v

8-7-6-X 2T: 950MHz :: 1.90v | 978MHz :: 2.00v
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