Test Setup

• CPU: Intel Core i7 965 Extreme Edition
  • CPU Clock: 3.20GHz
    
  • QPI: 6.4GT/s
    
  • IMC Clock: 2.67GHz
• Motherboard: Asus P6T Deluxe (0903 BIOS)
  
• Graphics Card: Zotac GeForce GTX 280
  
• PSU: PC Power and Cooling 750 Silencer
  
• Hard Drive: Seagate 7200.10 250GB SATA HDD
  
• OS: Windows Vista Home Premium 64-bit SP1
  
• Drivers: Nvidia Forceware 180.48 WHQL

Tests Run

Memory Speeds Tested

• 1,600MHz (3.2GHz IMC Clock, 1.66V Memory)
• 9-9-9-24-1T
  
• 8-8-8-21-1T
  
• G.Skill Low Latency: 7-7-7-17-1T (1.8V, 1.35V CPU, 1.35V Uncore)
  
• G.Skill Max OC: 1,780MHz (3.65GHz IMC, 3.65GHz, CPU, 5.34GT/s QPI, 1.8V Mem, 1.35V CPU, 1.4V Uncore)

We found that despite being able to boot in excess of 1,850MHz, the G.Skill memory was not stable until we dropped the whole system down to just 1,780MHz. The Samsung ICs will be happy all the way up to 2.0V, however we believe our limitation is still our CPU - the Uncore area which includes the memory controller seems more limited than the core clock overhead and is worth taking into account when buying very high performance Core i7 memory - can your CPU run its Uncore sector at 3.2GHz and above stable?