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For the past few months I've been testing Corsair's flag ship product, the Corsair Dominator GTs which are based on the new Elpida 50nmm DDR3 ICs - Elpida Hyper J1108BASE -MNH-E Hyper (or Elpida Hyper for short). The Elpida Hyper ICs are built using copper interconnects rather than aluminum - making CAS7 a reality at DDR3-2000Mhz at only 1.65v!

Corsair sent me a typical sealed white box packaged housing blister packed individual 2GB Dominator GT modules, along with new Corsair Airflow memory cooler and a Corsair Flash Voyager Mini USB flash drive. Seems the Voyager Mini USB flash drives won't be included in retail packaging.

Product page http://www.corsair.com/products/domi...t/default.aspx

SPD programmed at:

• XMP 7-8-7-20 2T values at 2000MHz at 1.65V Vdimm
• JEDEC standard 9-9-9-24 at 1333Mhz

Corsair disclaimer:

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Background:
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The 6GB Corsair Dominator GT DDR3-2000Mhz kit is validated for DDR3-2000Mhz 7-8-7-20 2T at 1.65v vdimm with Uncore validated at 1.6v. Uncore is key to memory clocks on Core i7/X58 platform and there requires a balance between vdimm and Uncore volts for Core i7 safety. On DFI uncore volts are termed CPU VTT, on Asus QPI/DRAM and on Gigabyte QPI/VTT. Since I'm using DFI UT X58-T3EH8 motherboard, I'll be referring to Uncore voltage as CPU VTT for the remainder of these tests.

Intel specified CPU VTT to max volts of 1.35v. And for Core i7 to remain safe, vdimm memory voltage needs to always be set within 0.5v of CPU VTT. So technically max vdimm for safe operation would be 1.35 + 0.5v = 1.85v vdimm. But folks have been benching at 1.55-1.65v CPU VTT to allow higher BCLK/Memory clock frequencies - the long term effects on Core i7 are unknown but I've been using CPU VTT for benching only between 1.21v to 1.65v with no problems for several months now with no adverse effects as yet. No one so far online has retailed retail Core i7 failing from such high CPU VTT/Vdimm settings as yet either.

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Before 4/28 Beta Bios
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Prior to 04/28 Beta bios, had some weird troubles getting this memory consistently single Super Pi 32M stable at rated speeds of DDR3-2000Mhz 7-8-7-20 2T (tried 1T as well) at 1.64v-1.66v vdimm. I tried CPU VTT between 1.4-1.66v and didn't help. Strange part is I'm 8x HCI memtest stable at 1.64v vdimm and 1.44v CPU VTT and can 3dmark at those settings @DDR3-2000Mhz 7-8-7-20 1T. I could even run 8x32M Pi (HyperPi) tests at higher memory frequencies than I could run single Super Pi 32M. Consistently, single Super Pi 32M stable was only around DDR3-1870Mhz 7-8-7-20 1T/2T at 1.64v on bioses prior to 04/28 Beta.

Luckily, I tried a second 6GB Corsair Dominator GT kit from Corsair which was better for single Super Pi 32M up to DDR3-2000Mhz 7-8-7-20 but beyond DDR3-2000Mhz, memory frequency still had single Super Pi 32M inconsistencies at memory frequencies which were lower than what I could achieve with 8x 32M Super Pi (Hyper Pi).

This single Super Pi 32M issue wasn't specific to DFI X58 boards, but also occurred with early EVGA X58 bios based boards as well. There was various discussed work arounds related adjusting Round Trip Latency (RTL) and DDRAM VREF voltages posted here.

With VREF adjustments on 2/27 beta bios DDR3-2209Mhz 7-8-7-20 1T was the maximum single Super Pi 32M I could achieve which was a huge improvement over what I could previously achieve on 2/27 beta and previous bioses. Although, the max CPUZ validation memory frequency was still a bit lower than what I could achieve on 1/23 beta bios.

@DDR3-2286Mhz 7-8-7-21 1T at 1.875v vdimm bios set (~1.880v real DMM)

Still not close to my best I did with 1/23 beta bios.

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After 4/28 Beta Bios
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Enter, DFI UT X58-T3EH8 pre-public 4/28 Beta bios, this bios dramatically changed the bios internals optimizing skew for Elpida based ICs and adding Round Trip Latency (RTL) and TREF options to memory settings page. 4/28 Beta bios improved my 6GB Corsair Dominator GT overclocks and consistency alot!.

The follow results below are with 4/28 beta bios and the second kit of Dominator GT's as first kit was sent back to Corsair who tested the memory fine on Asus P6T Deluxe.

System:

• i7 920 3836A756
• EK Supreme LT 1366 / FESER 480 / MCP655
• DFI UT X58-T3EH8 04/28 beta
• 2x HD4870x2 Crossfire (HIS + Gigabyte flashed to Asus Top bios) with ATI Win7 9.4 (8.612 WHQL)
• 6GB Corsair Dominator GT DDR3-2000Mhz 7-8-7-20
• 750GB Samsung SATAII
• Silverstone OP1200 PSU
• Triple boot - WinXP Pro SP3 / Vista Ultimate 64Bit SP2 / Win7 Ultimate 64bit RC

All benchmarks done in Windows 7 Ultimate 64bit RC

Benchmarks

• HyperPi v0.99b - 8x 32M Super Pi
• Single SuperPi v1.5 32M Pi
• LinX v0.5.8.2
• 3DMark Vantage
• Sandra 2009 Lite Memory Bandwidth
• Everest Ultimate 5.0.1.1732 Bandwidth

All results done with 12x memory multiplier unless otherwise stated.

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<< Click image for full size screenshots >>

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DDR3-2000Mhz 7-8-7-20 1T 1.65v
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DDR3-2050Mhz 7-8-7-20 1T at 1.665v
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DDR3-2100Mhz 7-8-7-20 1T at 1.725v
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